Charged particle cancer therapy patient positioning method and apparatus

ABSTRACT

The invention comprises a patient positioning method and apparatus used in conjunction with multi-axis charged particle or proton beam radiation therapy of cancerous tumors. The patient positioning system is used to translate the patient and/or rotate the patient into a zone where the proton beam can scan the tumor using a targeting system. The patient positioning system is optionally used in conjunction with systems used to constrain movement of the patient, such as semi-vertical, sitting, or laying positioning systems.

CROSS REFERENCES TO RELATED APPLICATIONS

This application:

-   -   is a continuation-in-part of U.S. patent application Ser. No.        12/425,683 filed Apr. 17, 2009, which claims the benefit of:        -   U.S. provisional patent application No. 61/055,395 filed May            22, 2008;        -   U.S. provisional patent application No. 61/137,574 filed            Aug. 1, 2008;        -   U.S. provisional patent application No. 61/192,245 filed            Sep. 17, 2008;        -   U.S. provisional patent application No. 61/055,409 filed May            22, 2008;        -   U.S. provisional patent application No. 61/203,308 filed            Dec. 22, 2008;        -   U.S. provisional patent application No. 61/188,407 filed            Aug. 11, 2008;        -   U.S. provisional patent application No. 61/188,406 filed            Aug. 11, 2008;        -   U.S. provisional patent application No. 61/189,815 filed            Aug. 25, 2008;        -   U.S. provisional patent application No. 61/201,731 filed            Dec. 15, 2008;        -   U.S. provisional patent application No. 61/205,362 filed            Jan. 21, 2009;        -   U.S. provisional patent application No. 61/134,717 filed            Jul. 14, 2008;        -   U.S. provisional patent application No. 61/134,707 filed            Jul. 14, 2008;        -   U.S. provisional patent application No. 61/201,732 filed            Dec. 15, 2008;        -   U.S. provisional patent application No. 61/198,509 filed            Nov. 7, 2008;        -   U.S. provisional patent application No. 61/134,718 filed            Jul. 14, 2008;        -   U.S. provisional patent application No. 61/190,613 filed            Sep. 2, 2008;        -   U.S. provisional patent application No. 61/191,043 filed            Sep. 8, 2008;        -   U.S. provisional patent application No. 61/192,237 filed            Sep. 17, 2008;        -   U.S. provisional patent application No. 61/201,728 filed            Dec. 15, 2008;        -   U.S. provisional patent application No. 61/190,546 filed            Sep. 2, 2008;        -   U.S. provisional patent application No. 61/189,017 filed            Aug. 15, 2008;        -   U.S. provisional patent application No. 61/198,248 filed            Nov. 5, 2008;        -   U.S. provisional patent application No. 61/198,508 filed            Nov. 7, 2008;        -   U.S. provisional patent application No. 61/197,971 filed            Nov. 3, 2008;        -   U.S. provisional patent application No. 61/199,405 filed            Nov. 17, 2008;        -   U.S. provisional patent application No. 61/199,403 filed            Nov. 17, 2008; and        -   U.S. provisional patent application No. 61/199,404 filed            Nov. 17, 2008;    -   claims the benefit of U.S. provisional patent application No.        61/209,529 filed Mar. 9, 2009;    -   claims the benefit of U.S. provisional patent application No.        61/208,182 filed Feb. 23, 2009;    -   claims the benefit of U.S. provisional patent application No.        61/208,971 filed Mar. 3, 2009; and    -   claims the benefit of U.S. provisional patent application No.        61/270,298 filed Jul. 7, 2009,    -   all of which are incorporated herein in their entirety by this        reference thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to treatment of solid cancers. Moreparticularly, the invention relates to a patient positioning system usedin conjunction with charged particle cancer therapy beam acceleration,extraction, and/or targeting methods and apparatus.

2. Discussion of the Prior Art

Cancer

A tumor is an abnormal mass of tissue. Tumors are either benign ormalignant. A benign tumor grows locally, but does not spread to otherparts of the body. Benign tumors cause problems because of their spread,as they press and displace normal tissues. Benign tumors are dangerousin confined places such as the skull. A malignant tumor is capable ofinvading other regions of the body. Metastasis is cancer spreading byinvading normal tissue and spreading to distant tissues.

Cancer Treatment

Several forms of radiation therapy exist for cancer treatment including:brachytherapy, traditional electromagnetic X-ray therapy, and protontherapy. Each are further described, infra.

Brachytherapy is radiation therapy using radioactive sources implantedinside the body. In this treatment, an oncologist implants radioactivematerial directly into the tumor or very close to it. Radioactivesources are also placed within body cavities, such as the uterinecervix.

The second form of traditional cancer treatment using electromagneticradiation includes treatment using X-rays and gamma rays. An X-ray ishigh-energy, ionizing, electromagnetic radiation that is used at lowdoses to diagnose disease or at high doses to treat cancer. An X-ray orRöntgen ray is a form of electromagnetic radiation with a wavelength inthe range of 10 to 0.01 nanometers (nm), corresponding to frequencies inthe range of 30 PHz to 30 EHz. X-rays are longer than gamma rays andshorter than ultraviolet rays. X-rays are primarily used for diagnosticradiography. X-rays are a form of ionizing radiation and as such can bedangerous. Gamma rays are also a form of electromagnetic radiation andare at frequencies produced by sub-atomic particle interactions, such aselectron-positron annihilation or radioactive decay. In theelectromagnetic spectrum, gamma rays are generally characterized aselectromagnetic radiation having the highest frequency, as havinghighest energy, and having the shortest wavelength, such as below about10 picometers. Gamma rays consist of high energy photons with energiesabove about 100 keV. X-rays are commonly used to treat cancerous tumors.However, X-rays are not optimal for treatment of cancerous tissue asX-rays deposit their highest does of radiation near the surface of thetargeted tissue and delivery exponentially less radiation as theypenetrate into the tissue. This results in large amounts of radiationbeing delivered outside of the tumor. Gamma rays have similarlimitations.

The third form of cancer treatment uses protons. Proton therapy systemstypically include: a beam generator, an accelerator, and a beamtransport system to move the resulting accelerated protons to aplurality of treatment rooms where the protons are delivered to a tumorin a patient's body.

Proton therapy works by aiming energetic ionizing particles, such asprotons accelerated with a particle accelerator, onto a target tumor.These particles damage the DNA of cells, ultimately causing their death.Cancerous cells, because of their high rate of division and theirreduced ability to repair damaged DNA, are particularly vulnerable toattack on their DNA.

Due to their relatively enormous size, protons scatter less easily inthe tissue and there is very little lateral dispersion. Hence, theproton beam stays focused on the tumor shape without much lateral damageto surrounding tissue. All protons of a given energy have a certainrange, defined by the Bragg peak, and the dosage delivery to tissueratio is maximum over just the last few millimeters of the particle'srange. The penetration depth depends on the energy of the particles,which is directly related to the speed to which the particles wereaccelerated by the proton accelerator. The speed of the proton isadjustable to the maximum rating of the accelerator. It is thereforepossible to focus the cell damage due to the proton beam at the verydepth in the tissues where the tumor is situated. Tissues situatedbefore the Bragg peak receive some reduced dose and tissues situatedafter the peak receive none.

Synchrotron

Patents related to the current invention are summarized here.

Proton Beam Therapy System

F. Cole, et. al. of Loma Linda University Medical Center “Multi-StationProton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989)describe a proton beam therapy system for selectively generating andtransporting proton beams from a single proton source and accelerator toa selected treatment room of a plurality of patient treatment rooms.

Extraction

T. Nakanishi, et. al. “Charged-Particle Beam Accelerator, Particle BeamRadiation Therapy System Using the Charged-Particle Beam Accelerator,and Method of Operating the Particle Beam Radiation Therapy System”,U.S. Pat. No. 7,122,978 (Oct. 17, 2006) describe a charged particle beamaccelerator having an RF-KO unit for increasing amplitude of betatronoscillation of a charged particle beam within a stable region ofresonance and an extraction quadrupole electromagnet unit for varying astable region of resonance. The RF-KO unit is operated within afrequency range in which the circulating beam does not go beyond aboundary of stable region of resonance and the extraction quadrupoleelectromagnet is operated with timing required for beam extraction.

T. Haberer, et. al. “Method and Device for Controlling a Beam ExtractionRaster Scan Irradiation Device for Heavy Ions or Protons”, U.S. Pat. No.7,091,478 (Aug. 15, 2006) describe a method for controlling beamextraction irradiation in terms of beam energy, beam focusing, and beamintensity for every accelerator cycle.

K. Hiramoto, et. al. “Accelerator and Medical System and OperatingMethod of the Same”, U.S. Pat. No. 6,472,834 (Oct. 29, 2002) describe acyclic type accelerator having a deflection electromagnet and four-poleelectromagnets for making a charged particle beam circulate, amulti-pole electromagnet for generating a stability limit of resonanceof betatron oscillation, and a high frequency source for applying a highfrequency electromagnetic field to the beam to move the beam to theoutside of the stability limit. The high frequency source generates asum signal of a plurality of alternating current (AC) signals of whichthe instantaneous frequencies change with respect to time, and of whichthe average values of the instantaneous frequencies with respect to timeare different. The system applies the sum signal via electrodes to thebeam.

K. Hiramoto, et. al. “Synchrotron Type Accelerator and Medical TreatmentSystem Employing the Same”, U.S. Pat. No. 6,087,670 (Jul. 11, 2000) andK. Hiramoto, et. al. “Synchrotron Type Accelerator and Medical TreatmentSystem Employing the Same”, U.S. Pat. No. 6,008,499 (Dec. 28, 1999)describe a synchrotron accelerator having a high frequency applying unitarranged on a circulating orbit for applying a high frequencyelectromagnetic field to a charged particle beam circulating and forincreasing amplitude of betatron oscillation of the particle beam to alevel above a stability limit of resonance. Additionally, for beamejection, four-pole divergence electromagnets are arranged: (1)downstream with respect to a first deflector; (2) upstream with respectto a deflecting electromagnet; (3) downstream with respect to thedeflecting electromagnet; and (4) and upstream with respect to a seconddeflector.

K. Hiramoto, et. al. “Circular Accelerator and Method and Apparatus forExtracting Charged-Particle Beam in Circular Accelerator”, U.S. Pat. No.5,363,008 (Nov. 8, 1994) describe a circular accelerator for extractinga charged-particle beam that is arranged to: (1) increase displacementof a beam by the effect of betatron oscillation resonance; (2) toincrease the betatron oscillation amplitude of the particles, which havean initial betatron oscillation within a stability limit for resonance;and (3) to exceed the resonance stability limit thereby extracting theparticles exceeding the stability limit of the resonance.

K. Hiramoto, et. al. “Method of Extracting Charged Particles fromAccelerator, and Accelerator Capable Carrying Out the Method, byShifting Particle Orbit”, U.S. Pat. No. 5,285,166 (Feb. 8, 1994)describe a method of extracting a charged particle beam. An equilibriumorbit of charged particles maintained by a bending magnet and magnetshaving multipole components greater than sextuple components is shiftedby a constituent element of the accelerator other than these magnets tochange the tune of the charged particles.

Dosage

K. Matsuda, et. al. “Particle Beam Irradiation System”, U.S. Pat. No.7,372,053 (Nov. 27, 2007) describe a particle beam irradiation systemensuring a more uniform dose distribution at an irradiation objectthrough use of a stop signal, which stops the output of the ion beamfrom the irradiation device.

H. Sakamoto, et. al. “Radiation Treatment Plan Making System andMethod”, U.S. Pat. No. 7,054,801 (May 30, 2006) describe a radiationexposure system that divides an exposure region into a plurality ofexposure regions and uses a radiation simulation to plan radiationtreatment conditions to obtain flat radiation exposure to the desiredregion.

G. Hartmann, et. al. “Method For Verifying the Calculated Radiation Doseof an Ion Beam Therapy System”, U.S. Pat. No. 6,799,068 (Sep. 28, 2004)describe a method for the verification of the calculated dose of an ionbeam therapy system that comprises a phantom and a discrepancy betweenthe calculated radiation dose and the phantom.

H. Brand, et. al. “Method for Monitoring the Irradiation Control of anIon Beam Therapy System”, U.S. Pat. No. 6,614,038 (Sep. 2, 2003)describe a method of checking a calculated irradiation control unit ofan ion beam therapy system, where scan data sets, control computerparameters, measuring sensor parameters, and desired current values ofscanner magnets are permanently stored.

T. Kan, et. al. “Water Phantom Type Dose Distribution DeterminingApparatus”, U.S. Pat. No. 6,207,952 (Mar. 27, 2001) describe a waterphantom type dose distribution apparatus that includes a closed watertank, filled with water to the brim, having an inserted sensor that isused to determine an actual dose distribution of radiation prior toradiation therapy.

Movable Patient

N. Rigney, et. al. “Patient Alignment System with External Measurementand Object Coordination for Radiation Therapy System”, U.S. Pat. No.7,199,382 (Apr. 3, 2007) describe a patient alignment system for aradiation therapy system that includes multiple external measurementdevices that obtain position measurements of movable components of theradiation therapy system. The alignment system uses the externalmeasurements to provide corrective positioning feedback to moreprecisely register the patient to the radiation beam.

Y. Muramatsu, et. al. “Medical Particle Irradiation Apparatus”, U.S.Pat. No. 7,030,396 (Apr. 18, 2006); Y. Muramatsu, et. al. “MedicalParticle Irradiation Apparatus”, U.S. Pat. No. 6,903,356 (Jun. 7, 2005);and Y. Muramatsu, et. al. “Medical Particle Irradiation Apparatus”, U.S.Pat. No. 6,803,591 (Oct. 12, 2004) all describe a medical particleirradiation apparatus having a rotating gantry, an annular frame locatedwithin the gantry such that is can rotate relative to the rotatinggantry, an anti-correlation mechanism to keep the frame from rotatingwith the gantry, and a flexible moving floor engaged with the frame issuch a manner to move freely with a substantially level bottom while thegantry rotates.

H. Nonaka, et. al. “Rotating Radiation Chamber for Radiation Therapy”,U.S. Pat. No. 5,993,373 (Nov. 30, 1999) describe a horizontal movablefloor composed of a series of multiple plates that are connected in afree and flexible manner, where the movable floor is moved in synchronywith rotation of a radiation beam irradiation section.

Respiration

K. Matsuda “Radioactive Beam Irradiation Method and Apparatus TakingMovement of the Irradiation Area Into Consideration”, U.S. Pat. No.5,538,494 (Jul. 23, 1996) describes a method and apparatus that enablesirradiation even in the case of a diseased part changing position due tophysical activity, such as breathing and heart beat. Initially, aposition change of a diseased body part and physical activity of thepatient are measured concurrently and a relationship therebetween isdefined as a function. Radiation therapy is performed in accordance tothe function.

Patient Positioning

Y. Nagamine, et. al. “Patient Positioning Device and Patient PositioningMethod”, U.S. Pat. Nos. 7,212,609 and 7,212,608 (May 1, 2007) describe apatient positioning system that compares a comparison area of areference X-ray image and a current X-ray image of a current patientlocation using pattern matching.

D. Miller, et. al. “Modular Patient Support System”, U.S. Pat. No.7,173,265 (Feb. 6, 2007) describe a radiation treatment system having apatient support system that includes a modularly expandable patient podand at least one immobilization device, such as a moldable foam cradle.

K. Kato, et. al. “Multi-Leaf Collimator and Medical System IncludingAccelerator”, U.S. Pat. No. 6,931,100 (Aug. 16, 2005); K. Kato, et. al.“Multi-Leaf Collimator and Medical System Including Accelerator”, U.S.Pat. No. 6,823,045 (Nov. 23, 2004); K. Kato, et. al. “Multi-LeafCollimator and Medical System Including Accelerator”, U.S. Pat. No.6,819,743 (Nov. 16, 2004); and K. Kato, et. al. “Multi-Leaf Collimatorand Medical System Including Accelerator”, U.S. Pat. No. 6,792,078 (Sep.14, 2004) all describe a system of leaf plates used to shortenpositioning time of a patient for irradiation therapy. Motor drivingforce is transmitted to a plurality of leaf plates at the same timethrough a pinion gear. The system also uses upper and lower aircylinders and upper and lower guides to position a patient.

Imaging

P. Adamee, et. al. “Charged Particle Beam Apparatus and Method forOperating the Same”, U.S. Pat. No. 7,274,018 (Sep. 25, 2007) and P.Adamee, et. al. “Charged Particle Beam Apparatus and Method forOperating the Same”, U.S. Pat. No. 7,045,781 (May 16, 2006) describe acharged particle beam apparatus configured for serial and/or parallelimaging of an object.

K. Hiramoto, et. al. “Ion Beam Therapy System and its Couch PositioningSystem”, U.S. Pat. No. 7,193,227 (Mar. 20, 2007) describe a ion beamtherapy system having an X-ray imaging system moving in conjunction witha rotating gantry.

C. Maurer, et. al. “Apparatus and Method for Registration of Images toPhysical Space Using a Weighted Combination of Points and Surfaces”,U.S. Pat. No. 6,560,354 (May 6, 2003) described a process of X-raycomputed tomography registered to physical measurements taken on thepatient's body, where different body parts are given different weights.Weights are used in an iterative registration process to determine arigid body transformation process, where the transformation function isused to assist surgical or stereotactic procedures.

M. Blair, et. al. “Proton Beam Digital Imaging System”, U.S. Pat. No.5,825,845 (Oct. 20, 1998) describe a proton beam digital imaging systemhaving an X-ray source that is movable into the treatment beam line thatcan produce an X-ray beam through a region of the body. By comparison ofthe relative positions of the center of the beam in the patientorientation image and the isocentre in the master prescription imagewith respect to selected monuments, the amount and direction of movementof the patient to make the best beam center correspond to the targetisocentre is determined.

S. Nishihara, et. al. “Therapeutic Apparatus”, U.S. Pat. No. 5,039,867(Aug. 13, 1991) describe a method and apparatus for positioning atherapeutic beam in which a first distance is determined on the basis ofa first image, a second distance is determined on the basis of a secondimage, and the patient is moved to a therapy beam irradiation positionon the basis of the first and second distances.

Problem

There exists in the art of particle beam therapy of cancerous tumors aneed for positioning a patient and a tumor thereof relative to a chargedparticle cancer therapy irradiation beam to ensure targeted andcontrolled delivery of energy to the cancerous tumor with minimizationof damage to surrounding healthy tissue. There further exists in the artof particle beam treatment of cancerous tumors in the body a need forefficient control of magnetic fields used in the control of chargedparticles in a synchrotron of a charged particle cancer therapy systemto deliver charged particles with a specified energy, intensity, and/ortiming of charged particle delivery relative to a patient's currentposition.

SUMMARY OF THE INVENTION

The invention comprises a patient positioning method and apparatus usedin conjunction with multi-axis controlled charged particle beamradiation therapy of cancerous tumors.

DESCRIPTION OF THE FIGURES

FIG. 1 illustrates component connections of a particle beam therapysystem;

FIG. 2 illustrates a charged particle therapy system;

FIG. 3 illustrates straight and turning sections of a synchrotron

FIG. 4 illustrates turning magnets of a synchrotron;

FIG. 5 provides a perspective view of a turning magnet;

FIG. 6 illustrates a cross-sectional view of a turning magnet;

FIG. 7 illustrates a cross-sectional view of a turning magnet;

FIG. 8 illustrates magnetic field concentration in a turning magnet;

FIG. 9 illustrates correction coils in a turning magnet;

FIG. 10 illustrates a magnetic turning section of a synchrotron;

FIG. 11 illustrates a magnetic field control system;

FIG. 12 illustrates a charged particle extraction and intensity controlsystem;

FIG. 13 illustrates a patient positioning system from: (A) a front viewand (B) a side view;

FIG. 14 illustrates multi-dimensional scanning of a charged particlebeam spot scanning system operating on: (A) a 2-D slice or (B) a 3-Dvolume of a tumor;

FIG. 15 illustrates an X-ray source proximate a particle beam path;

FIG. 16 illustrates a semi-vertical patient positioning system;

FIG. 17 illustrates a seated positioning system;

FIG. 18 illustrates a laying positioning system;

FIG. 19 illustrates a head restraint system;

FIG. 20 illustrates a head restraint system;

FIG. 21 illustrates hand and head supports;

FIG. 22 illustrates a back support; and

FIG. 23 illustrates a knee support.

DETAILED DESCRIPTION OF THE INVENTION

The invention comprises a patient positioning method and apparatus usedin conjunction with multi-axis controlled charged particle beamradiation therapy of cancerous tumors.

The patient is positioned using a patient positioning system of apatient interface module. The patient positioning system is used totranslate the patient and/or rotate the patient into a zone where theproton beam can scan the tumor using a proton targeting system.Essentially, the patient positioning system performs large movements ofthe patient to place the tumor near the center of a proton beam path andthe proton targeting system performs fine movements of the momentarybeam position of the proton beam in targeting the tumor. The patientpositioning system is optionally used in conjunction with systems usedto constrain movement of the patient, such as semi-vertical, sitting, orlaying positioning systems.

Used in conjunction with the positioning system, novel features of asynchrotron are described. Particularly, intensity control of a chargedparticle beam acceleration, extraction, and/or targeting method andapparatus used in conjunction with charged particle beam radiationtherapy of cancerous tumors is described. More particularly, intensitycontrol of a charged particle stream of a synchrotron is described.Intensity control is described in combination with turning or bendingmagnets, edge focusing magnets, concentrating magnetic field magnets,winding and control coils, and extraction elements of the synchrotron.The synchrotron control elements allow tight control of the chargedparticle beam, which compliments the tight control of patientpositioning to yield efficient treatment of a solid tumor with reducedtissue damage to surrounding healthy tissue. In addition, the systemreduces the overall size of the synchrotron, provides a tightlycontrolled proton beam, directly reduces the size of required magneticfields, directly reduces required operating power, and allows continualacceleration of protons in a synchrotron even during a process ofextracting protons from the synchrotron.

Cyclotron/Synchrotron

A cyclotron uses a constant magnetic field and a constant-frequencyapplied electric field. One of the two fields is varied in asynchrocyclotron. Both of these fields are varied in a synchrotron.Thus, a synchrotron is a particular type of cyclic particle acceleratorin which a magnetic field is used to turn the particles so theycirculate and an electric field is used to accelerate the particles. Thesynchrotron carefully synchronizes the applied fields with thetravelling particle beam.

By increasing the fields appropriately as the particles gain energy, thecharged particles path can be held constant as they are accelerated.This allows the vacuum container for the particles to be a large thintorus. In practice it is easier to use some straight sections betweenthe bending magnets and some turning sections giving the torus the shapeof a round-cornered polygon. A path of large effective radius is thusconstructed using simple straight and curved pipe segments, unlike thedisc-shaped chamber of the cyclotron type devices. The shape also allowsand requires the use of multiple magnets to bend the particle beam.

The maximum energy that a cyclic accelerator can impart is typicallylimited by the strength of the magnetic fields and the minimumradius/maximum curvature, of the particle path. In a cyclotron themaximum radius is quite limited as the particles start at the center andspiral outward, thus this entire path must be a self-supportingdisc-shaped evacuated chamber. Since the radius is limited, the power ofthe machine becomes limited by the strength of the magnetic field. Inthe case of an ordinary electromagnet, the field strength is limited bythe saturation of the core because when all magnetic domains are alignedthe field may not be further increased to any practical extent. Thearrangement of the single pair of magnets also limits the economic sizeof the device.

Synchrotrons overcome these limitations, using a narrow beam pipesurrounded by much smaller and more tightly focusing magnets. Theability of this device to accelerate particles is limited by the factthat the particles must be charged to be accelerated at all, but chargedparticles under acceleration emit photons, thereby losing energy. Thelimiting beam energy is reached when the energy lost to the lateralacceleration required to maintain the beam path in a circle equals theenergy added each cycle. More powerful accelerators are built by usinglarge radius paths and by using more numerous and more powerfulmicrowave cavities to accelerate the particle beam between corners.Lighter particles, such as electrons, lose a larger fraction of theirenergy when turning. Practically speaking, the energy ofelectron/positron accelerators is limited by this radiation loss, whileit does not play a significant role in the dynamics of proton or ionaccelerators. The energy of those is limited strictly by the strength ofmagnets and by the cost.

Charged Particle Beam Therapy

Throughout this document, a charged particle beam therapy system, suchas a proton beam, hydrogen ion beam, or carbon ion beam, is described.Herein, the charged particle beam therapy system is described using aproton beam. However, the aspects taught and described in terms of aproton beam are not intended to be limiting to that of a proton beam andare illustrative of a charged particle beam system. Any charged particlebeam system is equally applicable to the techniques described herein.

Referring now to FIG. 1, a charged particle beam system 100 isillustrated. The charged particle beam preferably comprises a number ofsubsystems including any of: a main controller 110; an injection system120; a synchrotron 130 that typically includes: (1) an acceleratorsystem 132 and (2) an extraction system 134; a targeting/delivery system140; a patient interface module 150; a display system 160; and/or animaging system 170.

An exemplary method of use of the charged particle beam system 100 isprovided. The main controller 110 controls one or more of the subsystemsto accurately and precisely deliver protons to a tumor of a patient. Forexample, the main controller 110 obtains an image, such as a portion ofa body and/or of a tumor, from the imaging system 170. The maincontroller 110 also obtains position and/or timing information from thepatient interface module 150. The main controller 110 then optionallycontrols the injection system 120 to inject a proton into a synchrotron130. The synchrotron typically contains at least an accelerator system132 and an extraction system 134. The main controller preferablycontrols the proton beam within the accelerator system, such as bycontrolling speed, trajectory, and timing of the proton beam. The maincontroller then controls extraction of a proton beam from theaccelerator through the extraction system 134. For example, thecontroller controls timing, energy, and/or intensity of the extractedbeam. The controller 110 also preferably controls targeting of theproton beam through the targeting/delivery system 140 to the patientinterface module 150. One or more components of the patient interfacemodule 150 are preferably controlled by the main controller 110.Further, display elements of the display system 160 are preferablycontrolled via the main controller 110. Displays, such as displayscreens, are typically provided to one or more operators and/or to oneor more patients. In one embodiment, the main controller 110 times thedelivery of the proton beam from all systems, such that protons aredelivered in an optimal therapeutic manner to the patient.

Herein, the main controller 110 refers to a single system controllingthe charged particle beam system 100, to a single controller controllinga plurality of subsystems controlling the charged particle beam system100, or to a plurality of individual controllers controlling one or moresub-systems of the charged particle beam system 100.

Synchrotron

Herein, the term synchrotron is used to refer to a system maintainingthe charged particle beam in a circulating path; however, cyclotrons arealternatively used, albeit with their inherent limitations of energy,intensity, and extraction control. Further, the charged particle beam isreferred to herein as circulating along a circulating path about acentral point of the synchrotron. The circulating path is alternativelyreferred to as an orbiting path; however, the orbiting path does notrefer a perfect circle or ellipse, rather it refers to cycling of theprotons around a central point or region.

Referring now to FIG. 2, an illustrative exemplary embodiment of oneversion of the charged particle beam system 100 is provided. The number,position, and described type of components is illustrative andnon-limiting in nature. In the illustrated embodiment, the injectionsystem 120 or ion source or charged particle beam source generatesprotons. The protons are delivered into a vacuum tube that runs into,through, and out of the synchrotron. The generated protons are deliveredalong an initial path 262. Focusing magnets 230, such as quadrupolemagnets or injection quadrupole magnets, are used to focus the protonbeam path. A quadrupole magnet is a focusing magnet. An injector bendingmagnet 232 bends the proton beam toward the plane of the synchrotron130. The focused protons having an initial energy are introduced into aninjector magnet 240, which is preferably an injection Lamberson magnet.Typically, the initial beam path 262 is along an axis off of, such asabove, a circulating plane of the synchrotron 130. The injector bendingmagnet 232 and injector magnet 240 combine to move the protons into thesynchrotron 130. Main bending or turning magnets, dipole magnets, orcirculating magnets 250 are used to turn the protons along a circulatingbeam path 264. A dipole magnet is a bending magnet. The main bendingmagnets 250 bend the initial beam path 262 into a circulating beam path264. In this example, the main bending magnets 250 or circulatingmagnets are represented as four sets of four magnets to maintain thecirculating beam path 264 into a stable circulating beam path. However,any number of magnets or sets of magnets are optionally used to move theprotons around a single orbit in the circulation process. The protonspass through an accelerator 270. The accelerator accelerates the protonsin the circulating beam path 264. As the protons are accelerated, thefields applied by the magnets 250 are increased. Particularly, the speedof the protons achieved by the accelerator 270 are synchronized withmagnetic fields of the main bending magnets 250 or circulating magnetsto maintain stable circulation of the protons about a central point orregion 280 of the synchrotron. At separate points in time theaccelerator 270/main bending magnet 250 combination is used toaccelerate and/or decelerate the circulating protons while maintainingthe protons in the circulating path or orbit. An extraction element ofthe inflector/deflector system 290 is used in combination with aLamberson extraction magnet 292 to remove protons from their circulatingbeam path 264 within the synchrotron 130. One example of a deflectorcomponent is a Lamberson magnet. Typically the deflector moves theprotons from the circulating plane to an axis off of the circulatingplane, such as above the circulating plane. Extracted protons arepreferably directed and/or focused using an extraction bending magnet237 and extraction focusing magnets 235, such as quadrupole magnetsalong a transport path 268 into the scanning/targeting/delivery system140. Two components of a scanning system 140 or targeting systemtypically include a first axis control 142, such as a vertical control,and a second axis control 144, such as a horizontal control. In oneembodiment, the first axis control 142 allows for about 100 mm ofvertical or y-axis scanning of the proton beam 268 and the second axiscontrol 144 allows for about 700 mm of horizontal or x-axis scanning ofthe proton beam 268. A nozzle system is optionally used for imaging theproton beam and/or as a vacuum barrier between the low pressure beampath of the synchrotron and the atmosphere. Protons are delivered withcontrol to the patient interface module 150 and to a tumor of a patient.All of the above listed elements are optional and may be used in variouspermutations and combinations. Use of the above listed elements isfurther described, infra. Protons are delivered with control to thepatient interface module 170 and to a tumor of a patient.

In one example, the charged particle irradiation includes a synchrotronhaving: a center, straight sections, and turning sections. The chargedparticle beam path runs about the center, through the straight sections,and through the turning sections, where each of the turning sectionscomprises a plurality of bending magnets. Preferably, the circulationbeam path comprises a length of less than sixty meters, and the numberof straight sections equals the number of turning sections. Preferablyno quadrupoles are used in or around the circulating path of thesynchrotron.

Circulating System

A synchrotron 130 preferably comprises a combination of straightsections 310 and ion beam turning sections 320. Hence, the circulatingpath of the protons is not circular in a synchrotron, but is rather apolygon with rounded corners.

In one illustrative embodiment, the synchrotron 130, which is alsoreferred to as an accelerator system, has four straight elements andfour turning sections. Examples of straight sections 310 include the:inflector 240, accelerator 270, extraction system 290, and deflector292. Along with the four straight sections are four ion beam turningsections 320, which are also referred to as magnet sections or turningsections. Turning sections are further described, infra.

Referring now to FIG. 3, an exemplary synchrotron is illustrated. Inthis example, protons delivered along the initial path 262 are inflectedinto the circulating beam path with the inflector 240 and afteracceleration are extracted via a deflector 292 to a beam transport path268. In this example, the synchrotron 130 comprises four straightsections 310 and four turning sections 320 where each of the fourturning sections use one or more magnets to turn the proton beam aboutninety degrees. As is further described, infra, the ability to closelyspace the turning sections and efficiently turn the proton beam resultsin shorter straight sections. Shorter straight sections allows for asynchrotron design without the use of focusing quadrupoles in thecirculating beam path of the synchrotron. The removal of the focusingquadrupoles from the circulating proton beam path results in a morecompact design. In this example, the illustrated synchrotron has about afive meter diameter versus eight meter and larger cross-sectionaldiameters for systems using a quadrupole focusing magnet in thecirculating proton beam path.

Referring now to FIG. 4, additional description of the first turningsection 320 is provided. Each of the turning sections preferablycomprises multiple magnets, such as about 2, 4, 6, 8, 10, or 12 magnets.In this example, four turning magnets 410, 420, 430, 440 in the firstturning section 320 are used to illustrate key principles, which are thesame regardless of the number of magnets in a turning section 320. Aturning magnet 410 is a particular type of circulating magnet 250.

In physics, the Lorentz force is the force on a point charge due toelectromagnetic fields. The Lorentz force is given by the equation 1 interms of magnetic fields with the election field terms not included.

F=q(v×B)  eq. 1

In equation 1, F is the force in newtons; B is the magnetic field inTeslas; and v is the instantaneous velocity of the particles in metersper second.

Referring now to FIG. 5, an example of a single magnet turning section410 is expanded. The turning section includes a gap 510. The gap ispreferably a flat gap, allowing for a magnetic field across the gap thatis more uniform, even, and intense. A magnetic field enters the gapthrough a magnetic field incident surface and exits the gap through amagnetic field exiting surface. The gap 510 runs in a vacuum tubebetween two magnet halves. The gap is controlled by at least twoparameters: (1) the gap 510 is kept as large as possible to minimizeloss of protons and (2) the gap 510 is kept as small as possible tominimize magnet sizes and the associated size and power requirements ofthe magnet power supplies. The flat nature of the gap 510 allows for acompressed and more uniform magnetic field across the gap. One exampleof a gap dimension is to accommodate a vertical proton beam size ofabout two centimeters with a horizontal beam size of about five to sixcentimeters.

As described, supra, a larger gap size requires a larger power supply.For instance, if the gap size doubles in vertical size, then the powersupply requirements increase by about a factor of four. The flatness ofthe gap is also important. For example, the flat nature of the gapallows for an increase in energy of the extracted protons from about 250to about 330 MeV. More particularly, if the gap 510 has an extremelyflat surface, then the limits of a magnetic field of an iron magnet arereachable. An exemplary precision of the flat surface of the gap 510 isa polish of less than about five microns and preferably with a polish ofabout one to three microns. Unevenness in the surface results inimperfections in the applied magnetic field. The polished flat surfacespreads unevenness of the applied magnetic field.

Still referring to FIG. 5, the charged particle beam moves through thegap with an instantaneous velocity, v. A first magnetic coil 520 and asecond magnetic coil 530 run above and below the gap 510, respectively.Current running through the coils 520, 530 results in a magnetic field,B, running through the single magnet turning section 410. In thisexample, the magnetic field, B, runs upward, which results in a force,F, pushing the charged particle beam inward toward a central point ofthe synchrotron, which turns the charged particle beam in an arc.

Still referring to FIG. 5, a portion of an optional second magnetturning section 420 is illustrated. The coils 520, 530 typically havereturn elements 540, 550 or turns at the end of one magnet, such as atthe end of the first magnet turning section 410. The return elements orturns 540, 550 take space. The space reduces the percentage of the pathabout one orbit of the synchrotron that is covered by the turningmagnets. This leads to portions of the circulating path where theprotons are not turned and/or focused and allows for portions of thecirculating path where the proton path defocuses. Thus, the spaceresults in a larger synchrotron. Therefore, the space between magnetturning sections 560 is preferably minimized. The second turning magnetis used to illustrate that the coils 520, 530 optionally run along aplurality of magnets, such as 2, 3, 4, 5, 6, or more magnets. Coils 520,530 running across turning section magnets allows for two turningsection magnets to be spatially positioned closer to each other due tothe removal of the steric constraint of the turns, which reduces and/orminimizes the space 560 between two turning section magnets.

Referring now to FIGS. 6 and 7, two illustrative 90 degree rotatedcross-sections of single magnet turning sections 410 are presented. Themagnet assembly has a first magnet 610 and a second magnet 620. Amagnetic field induced by coils, described infra, runs between the firstmagnet 610 to the second magnet 620 across the gap 510. Return magneticfields run through a first yoke 612 and second yoke 622. The chargedparticles run through the vacuum tube in the gap. As illustrated,protons run into FIG. 6 through the gap 510 and the magnetic field,illustrated as vector, B, that applies a force, F, to the protonspushing the protons towards the center of the synchrotron, which is offpage to the right in FIG. 6. The magnetic field is created usingwindings. A first coil is wound about the magnet to form a first windingcoil 650. The second coil of wire makes up a second winding coil 660.Isolating gaps 630, 640, such as air gaps, isolate the iron based yokes612, 622 from the gap 510. The gap is approximately flat to yield auniform magnetic field across the gap, as described supra.

Referring again to FIG. 7, the ends of a single turning magnet arepreferably beveled. Nearly perpendicular or right angle edges of aturning magnet 410 are represented by a dashed lines 674, 684.Preferably, the edge of the turning magnet is beveled at angles alpha,α, and beta, β, which is the off perpendicular angle between the rightangles 674, 684 and beveled edges 672, 682. The angle alpha is used todescribe the effect and the description of angle alpha applies to anglebeta, but angle alpha is optionally different from angle beta. The anglealpha provides an edge focusing effect. Beveling the edge of the turningmagnet 410 at angle alpha focuses the proton beam.

Multiple turning magnets provide multiple magnet edges that each haveedge focusing effects in the synchrotron 310. If only one turning magnetis used, then the beam is only focused once for angle alpha or twice forangle alpha and angle beta. However, by using smaller turning magnets,more turning magnets fit into the turning sections 320 of thesynchrotron 310. For example, if four magnets are used in a turningsection 320 of the synchrotron, then there are eight possible edgefocusing effect surfaces, two edges per magnet. The eight focusingsurfaces yield a smaller cross-sectional beam size. This allows the useof a smaller gap 510.

The use of multiple edge focusing effects in the turning magnets resultsin not only a smaller gap, but also the use of smaller magnets andsmaller power supplies. For a synchrotron 310 having four turningsections 320 where each turning sections has four turning magnets andeach turning magnet has two focusing edges, a total of thirty-twofocusing edges exist for each orbit of the protons in the circulatingpath of the synchrotron 310. Similarly, if 2, 6, or 8 magnets are usedin a given turning section, or if 2, 3, 5, or 6 turning sections areused, then the number of edge focusing surfaces expands or contractsaccording to equation 2.

$\begin{matrix}{{TFE} = {{NTS}*\frac{M}{NTS}*\frac{FE}{M}}} & {{eq}.\mspace{14mu} 2}\end{matrix}$

where TFE is the number of total focusing edges, NTS is the number ofturning section, M is the number of magnets, and FE is the number offocusing edges. Naturally, not all magnets are necessarily beveled andsome magnets are optionally beveled on only one edge.

The inventors have determined that multiple smaller magnets havebenefits over fewer larger magnets. For example, the use of 16 smallmagnets yields 32 focusing edges whereas the use of 4 larger magnetsyields only 8 focusing edges. The use of a synchrotron having morefocusing edges results in a circulating path of the synchrotron builtwithout the use of focusing quadrupoles magnets. All prior artsynchrotrons use quadrupoles in the circulating path of the synchrotron.Further, the use of quadrupoles in the circulating path necessitatesadditional straight sections in the circulating path of the synchrotron.Thus, the use of quadrupoles in the circulating path of a synchrotronresults in synchrotrons having larger diameters or largercircumferences.

In various embodiments of the system described herein, the synchrotronhas:

-   -   at least 4 and preferably 6, 8, 10, or more edge focusing edges        per 90 degrees of turn of the charged particle beam in a        synchrotron having four turning sections;    -   at least about 16 and preferably about 24, 32, or more edge        focusing edges per orbit of the charged particle beam in the        synchrotron;    -   only 4 turning sections where each of the turning sections        includes at least 4 and preferably 8 edge focusing edges;    -   an equal number of straight sections and turning sections;    -   exactly 4 turning sections;    -   at least 4 edge focusing edges per turning section;    -   no quadrupoles in the circulating path of the synchrotron;    -   a rounded corner rectangular polygon configuration;    -   a circumference of less than 60 meters;    -   a circumference of less than 60 meters and 32 edge focusing        surfaces; and/or    -   any of about 8, 16, 24, or 32 non-quadrupole magnets per        circulating path of the synchrotron, where the non-quadrupole        magnets include edge focusing edges.

Referring now to FIG. 6, the incident magnetic field surface 670 of thefirst magnet 610 is further described. FIG. 6 is not to scale and isillustrative in nature. Local imperfections or unevenness in quality ofthe finish of the incident surface 670 results in inhomogeneities orimperfections in the magnetic field applied to the gap 510. Preferably,the incident surface 670 is flat, such as to within about a zero tothree micron finish polish, or less preferably to about a ten micronfinish polish.

Referring now to FIG. 8, additional magnet elements, of the magnetcross-section illustratively represented in FIG. 6, are described. Thefirst magnet 610 preferably contains an initial cross-sectional distance810 of the iron based core. The contours of the magnetic field areshaped by the magnets 610, 620 and the yokes 612, 622. The iron basedcore tapers to a second cross-sectional distance 820. The magnetic fieldin the magnet preferentially stays in the iron based core as opposed tothe gaps 630, 640. As the cross-sectional distance decreases from theinitial cross-sectional distance 810 to the final cross-sectionaldistance 820, the magnetic field concentrates. The change in shape ofthe magnet from the longer distance 810 to the smaller distance 820 actsas an amplifier. The concentration of the magnetic field is illustratedby representing an initial density of magnetic field vectors 830 in theinitial cross-section 810 to a concentrated density of magnetic fieldvectors 840 in the final cross-section 820. The concentration of themagnetic field due to the geometry of the turning magnets results infewer winding coils 650, 660 being required and also a smaller powersupply to the coils being required.

Example I

In one example, the initial cross-section distance 810 is about fifteencentimeters and the final cross-section distance 820 is about tencentimeters. Using the provided numbers, the concentration of themagnetic field is about 15/10 or 1.5 times at the incident surface 670of the gap 510, though the relationship is not linear. The taper 860 hasa slope, such as about 20 to 60 degrees. The concentration of themagnetic field, such as by 1.5 times, leads to a corresponding decreasein power consumption requirements to the magnets.

Referring now to FIG. 9, an additional example of geometry of the magnetused to concentrate the magnetic field is illustrated. As illustrated inFIG. 8, the first magnet 610 preferably contains an initialcross-sectional distance 810 of the iron based core. The contours of themagnetic field are shaped by the magnets 610, 620 and the yokes 612,622. In this example, the core tapers to a second cross-sectionaldistance 820 with a smaller angle theta, θ. As described, supra, themagnetic field in the magnet preferentially stays in the iron based coreas opposed to the gaps 630, 640. As the cross-sectional distancedecreases from the initial cross-sectional distance 810 to the finalcross-sectional distance 820, the magnetic field concentrates. Thesmaller angle, theta, results in a greater amplification of the magneticfield in going from the longer distance 810 to the smaller distance 820.The concentration of the magnetic field is illustrated by representingan initial density of magnetic field vectors 830 in the initialcross-section 810 to a concentrated density of magnetic field vectors840 in the final cross-section 820. The concentration of the magneticfield due to the geometry of the turning magnets results in fewerwinding coils 650, 660 being required and also a smaller power supply tothe winding coils 650, 660 being required.

Still referring to FIG. 9, optional correction coils 910, 920 areillustrated that are used to correct the strength of one or more turningmagnets. The correction coils 920, 930 supplement the winding coils 650,660. The correction coils 910, 920 have correction coil power suppliesthat are separate from winding coil power supplies used with the windingcoils 650, 660. The correction coil power supplies typically operate ata fraction of the power required compared to the winding coil powersupplies, such as about 1, 2, 3, 5, 7, or 10 percent of the power andmore preferably about 1 or 2 percent of the power used with the windingcoils 650, 660. The smaller operating power applied to the correctioncoils 920, 920 allows for more accurate and/or precise control of thecorrection coils. The correction coils are used to adjust forimperfection in the turning magnets 410, 420.

Referring now to FIG. 10, an example of winding coils and correctioncoils about a plurality of turning magnets in an ion beam turningsection is illustrated. The winding coils preferably cover 1, 2, or 4turning magnets. In the illustrated example, a winding coil 1030 windsaround two turning magnets 410, 420 generating a magnetic field.Correction coils are used to correct the magnetic field strength of oneor more turning or bending magnets. In the illustrated example, a firstcorrection coil 1010 corrects a single turning magnet. Combined in theillustration, but separately implemented, a second correction coil 1020corrects two turning magnets 410, 420. The correction coils supplementthe winding coils. The correction coils have correction coil powersupplies that are separate from winding coil power supplies used withthe winding coils. The correction coil power supplies typically operateat a fraction of the power required compared to the winding coil powersupplies, such as about 1, 2, 3, 5, 7, or 10 percent of the power andmore preferably about 1 or 2 percent of the power used with the windingcoils. The smaller operating power applied to the correction coilsallows for more accurate and/or precise control of the correction coils.More particularly, a magnetic field produced by the first correctioncoil 1010 is used to adjust for imperfection in a magnetic fieldproduced by the turning magnet 410 or the second correction coil 1020 isused to adjust for imperfection in the turning magnet sections 610, 620.Optionally, separate correction coils are used for each turning magnetallowing individual tuning of the magnetic field for each turningmagnet, which eases quality requirements in the manufacture of eachturning magnet.

Correction coils are preferably used in combination with magnetic fieldconcentration magnets to stabilize a magnetic field in a synchrotron.For example, high precision magnetic field sensors 1050 are used tosense a magnetic field created in one or more turning magnets usingwinding elements. The sensed magnetic field is sent via a feedback loopto a magnetic field controller that adjusts power supplied to correctioncoils. The correction coils, operating at a lower power, are capable ofrapid adjustment to a new power level. Hence, via the feedback loop, thetotal magnetic field applied by the turning magnets and correction coilsis rapidly adjusted to a new strength, allowing continuous adjustment ofthe energy of the proton beam. In further combination, a novelextraction system allows the continuously adjustable energy level of theproton beam to be extracted from the synchrotron.

For example, one or more high precision magnetic field sensors 1050 areplaced into the synchrotron and are used to measure the magnetic fieldat or near the proton beam path. For example, the magnetic sensors areoptionally placed between turning magnets and/or within a turningmagnet, such as at or near the gap 510 or at or near the magnet core oryoke. The sensors are part of a feedback system to the correction coils,which is optionally run by the main controller 110. The feedback systemis controlled by the main controller 110 or a subunit or sub-function ofthe main controller 110. Thus, the system preferably stabilizes themagnetic field in the synchrotron elements rather than stabilizing thecurrent applied to the magnets. Stabilization of the magnetic fieldallows the synchrotron to come to a new energy level quickly.

Optionally, the one or more high precision magnetic field sensors areused to coordinate synchrotron beam energy and timing with patientrespiration. Stabilization of the magnetic field allows the synchrotronto come to a new energy level quickly. This allows the system to becontrolled to an operator or algorithm selected energy level with eachpulse of the synchrotron and/or with each breath of the patient.

The winding and/or correction coils correct 1, 2, 3, or 4 turningmagnets, and preferably correct a magnetic field generated by twoturning magnets. A winding or correction coil covering multiple magnetsreduces space between magnets as fewer winding or correction coil endsare required, which occupy space.

Example II

Referring now to FIG. 11, an example is used to clarify the magneticfield control using a feedback loop 1100 to change delivery times and/orperiods of proton pulse delivery. In one case, a respiratory sensor 1110senses the breathing cycle of the subject. The respiratory sensor sendsthe information to an algorithm in a magnetic field controller 1120,typically via the patient interface module 150 and/or via the maincontroller 110 or a subcomponent thereof. The algorithm predicts and/ormeasures when the subject is at a particular point in the breathingcycle, such as at the bottom of a breath. Magnetic field sensors 1130,such as the high precision magnetic field sensors, are used as input tothe magnetic field controller, which controls a magnet power supply 1140for a given magnetic field 1150, such as within a first turning magnet410 of a synchrotron 130. The control feedback loop is thus used to dialthe synchrotron to a selected energy level and deliver protons with thedesired energy at a selected point in time, such as at the bottom of thebreath. More particularly, the synchrotron accelerates the protons andthe control feedback loop keeps the protons in the circulating path bysynchronously adjusting the magnetic field strength of the turningmagnets. Intensity of the proton beam is also selectable at this stage.The feedback control to the correction coils allows rapid selection ofenergy levels of the synchrotron that are tied to the patient'sbreathing cycle. This system is in stark contrast to a system where thecurrent is stabilized and the synchrotron deliver pulses with a period,such as 10 or 20 cycles second with a fixed period.

The feedback or the magnetic field design coupled with the correctioncoils allows for the extraction cycle to match the varying respiratoryrate of the patient.

Traditional extraction systems do not allow this control as magnets havememories in terms of both magnitude and amplitude of a sine wave. Hence,in a traditional system, in order to change frequency, slow changes incurrent must be used. However, with the use of the feedback loop usingthe magnetic field sensors, the frequency and energy level of thesynchrotron are rapidly adjustable. Further aiding this process is theuse of a novel extraction system that allows for acceleration of theprotons during the extraction process, described infra.

Example III

Referring again to FIG. 10, an example of a winding coil 1030 thatcovers two turning magnets 410, 420 is provided. As described, supra,this system reduces space between turning sections allowing moremagnetic field to be applied per radian of turn. A first correction coil1010 is illustrated that is used to correct the magnetic field for thefirst turning magnet 410. Individual correction coils for each turningmagnet are preferred and individual correction coils yield the mostprecise and/or accurate magnetic field in each turning section.Particularly, the individual correction coil 1010 is used to compensatefor imperfections in the individual magnet of a given turning section.Hence, with a series of magnetic field sensors, corresponding magneticfields are individually adjustable in a series of feedback loops, via amagnetic field monitoring system 1030, which is preferably a subunit ofthe main controller 110. In one case, an independent coil is used foreach turning section magnet. Alternatively, a multiple magnet correctioncoil 1020 is used to correct the magnetic field for a plurality ofturning section magnets.

Flat Gap Surface

While the gap surface is described in terms of the first turning magnet410, the discussion applies to each of the turning magnets in thesynchrotron. Similarly, while the gap 510 surface is described in termsof the magnetic field incident surface 670, the discussion additionallyoptionally applies to the magnetic field exiting surface 680.

The magnetic field incident surface 670 of the first magnet 610 ispreferably about flat, such as to within about a zero to three micronfinish polish or less preferably to about a ten micron finish polish. Bybeing very flat, the polished surface spreads the unevenness of theapplied magnetic field across the gap 510. The very flat surface, suchas about 0, 1, 2, 4, 6, 8, 10, 15, or 20 micron finish, allows for asmaller gap size, a smaller applied magnetic field, smaller powersupplies, and tighter control of the proton beam cross-sectional area.

Proton Beam Extraction

Referring now to FIG. 12, an exemplary proton extraction process fromthe synchrotron 130 is illustrated. For clarity, FIG. 12 removeselements represented in FIG. 2, such as the turning magnets, whichallows for greater clarity of presentation of the proton beam path as afunction of time. Generally, protons are extracted from the synchrotron130 by slowing the protons. As described, supra, the protons wereinitially accelerated in a circulating path 264, which is maintainedwith a plurality of turning magnets 250. The circulating path isreferred to herein as an original central beamline 264. The protonsrepeatedly cycle around a central point in the synchrotron 280. Theproton path traverses through an RF cavity system 1210. To initiateextraction, an RF field is applied across a first blade 1212 and asecond blade 1214, in the RF cavity system 1210. The first blade 1212and second blade 1214 are referred to herein as a first pair of blades.

In the proton extraction process, a radio-frequency (RF) voltage isapplied across the first pair of blades, where the first blade 1212 ofthe first pair of blades is on one side of the circulating proton beampath 264 and the second blade 1214 of the first pair of blades is on anopposite side of the circulating proton beam path 264. The applied RFfield applies energy to the circulating charged-particle beam. Theapplied RF field alters the orbiting or circulating beam path slightlyof the protons from the original central beamline 264 to an alteredcirculating beam path 265. Upon a second pass of the protons through theRF cavity system, the RF field further moves the protons off of theoriginal proton beamline 264. For example, if the original beamline isconsidered as a circular path, then the altered beamline is slightlyelliptical. The applied RF field is timed to apply outward or inwardmovement to a given band of protons circulating in the synchrotronaccelerator. Each orbit of the protons is slightly more off axiscompared to the original circulating beam path 264. Successive passes ofthe protons through the RF cavity system are forced further and furtherfrom the original central beamline 264 by altering the direction and/orintensity of the RF field with each successive pass of the proton beamthrough the RF field.

The RF voltage is frequency modulated at a frequency about equal to theperiod of one proton cycling around the synchrotron for one revolutionor at a frequency than is an integral multiplier of the period of oneproton cycling about the synchrotron. The applied RF frequency modulatedvoltage excites a betatron oscillation. For example, the oscillation isa sine wave motion of the protons. The process of timing the RF field toa given proton beam within the RF cavity system is repeated thousands oftimes with successive passes of the protons being moved approximatelyone micrometer further off of the original central beamline 264. Forclarity, the effect of the approximately 1000 changing beam paths witheach successive path of a given band of protons through the RF field areillustrated as the altered beam path 265.

With a sufficient sine wave betatron amplitude, the altered circulatingbeam path 265 touches a material 1230, such as a foil or a sheet offoil. The foil is preferably a lightweight material, such as beryllium,a lithium hydride, a carbon sheet, or a material of low nuclear charge.A material of low nuclear charge is a material composed of atomsconsisting essentially of atoms having six or fewer protons. The foil ispreferably about 10 to 150 microns thick, is more preferably 30 to 100microns thick, and is still more preferably 40-60 microns thick. In oneexample, the foil is beryllium with a thickness of about 50 microns.When the protons traverse through the foil, energy of the protons islost and the speed of the protons is reduced. Typically, a current isalso generated, described infra. Protons moving at a slower speed travelin the synchrotron with a reduced radius of curvature 266 compared toeither the original central beamline 264 or the altered circulating path265. The reduced radius of curvature 266 path is also referred to hereinas a path having a smaller diameter of trajectory or a path havingprotons with reduced energy. The reduced radius of curvature 266 istypically about two millimeters less than a radius of curvature of thelast pass of the protons along the altered proton beam path 265.

The thickness of the material 1230 is optionally adjusted to created achange in the radius of curvature, such as about ½, 1, 2, 3, or 4 mmless than the last pass of the protons 265 or original radius ofcurvature 264. Protons moving with the smaller radius of curvaturetravel between a second pair of blades. In one case, the second pair ofblades is physically distinct and/or are separated from the first pairof blades. In a second case, one of the first pair of blades is also amember of the second pair of blades. For example, the second pair ofblades is the second blade 1214 and a third blade 1216 in the RF cavitysystem 1210. A high voltage DC signal, such as about 1 to 5 kV, is thenapplied across the second pair of blades, which directs the protons outof the synchrotron through a deflector 292, such as a Lamberson magnet,into a transport path 268.

Control of acceleration of the charged particle beam path in thesynchrotron with the accelerator and/or applied fields of the turningmagnets in combination with the above described extraction system allowsfor control of the intensity of the extracted proton beam, whereintensity is a proton flux per unit time or the number of protonsextracted as a function of time. For example, when a current is measuredbeyond a threshold, the RF field modulation in the RF cavity system isterminated or reinitiated to establish a subsequent cycle of proton beamextraction. This process is repeated to yield many cycles of proton beamextraction from the synchrotron accelerator.

Because the extraction system does not depend on any change any changein magnetic field properties, it allows the synchrotron to continue tooperate in acceleration or deceleration mode during the extractionprocess. Stated differently, the extraction process does not interferewith synchrotron. In stark contrast, traditional extraction systemsintroduce a new magnetic field, such as via a hexapole, during theextraction process. More particularly, traditional synchrotrons have amagnet, such as a hexapole magnet, that is off during an accelerationstage. During the extraction phase, the hexapole magnetic field isintroduced to the circulating path of the synchrotron. The introductionof the magnetic field necessitates two distinct modes, an accelerationmode and an extraction mode, which are mutually exclusive in time.

Charged Particle Beam Intensity Control

Control of applied field, such as a radio-frequency (RF) field,frequency and magnitude in the RF cavity system 1210 allows forintensity control of the extracted proton beam, where intensity isextracted proton flux per unit time or the number of protons extractedas a function of time.

Referring still to FIG. 12, when protons in the proton beam hit thematerial 1230 electrons are given off resulting in a current. Theresulting current is converted to a voltage and is used as part of a ionbeam intensity monitoring system or as part of an ion beam feedback loopfor controlling beam intensity. The voltage is optionally measured andsent to the main controller 110 or to a controller subsystem 1240. Moreparticularly, when protons in the charged particle beam path passthrough the material 1230, some of the protons lose a small fraction oftheir energy, such as about one-tenth of a percent, which results in asecondary electron. That is, protons in the charged particle beam pushsome electrons when passing through material 1230 giving the electronsenough energy to cause secondary emission. The resulting electron flowresults in a current or signal that is proportional to the number ofprotons going through the target material 1230. The resulting current ispreferably converted to voltage and amplified. The resulting signal isreferred to as a measured intensity signal.

The amplified signal or measured intensity signal resulting from theprotons passing through the material 1230 is preferably used incontrolling the intensity of the extracted protons. For example, themeasured intensity signal is compared to a goal signal, which ispredetermined in an irradiation of the tumor plan. The differencebetween the measured intensity signal and the planned for goal signal iscalculated. The difference is used as a control to the RF generator.Hence, the measured flow of current resulting from the protons passingthrough the material 1230 is used as a control in the RF generator toincrease or decrease the number of protons undergoing betatronoscillation and striking the material 1230. Hence, the voltagedetermined off of the material 1230 is used as a measure of the orbitalpath and is used as a feedback control to control the RF cavity system.Alternatively, the measured intensity signal is not used in the feedbackcontrol and is just used as a monitor of the intensity of the extractedprotons.

As described, supra, the photons striking the material 1230 is a step inthe extraction of the protons from the synchrotron 130. Hence, themeasured intensity signal is used to change the number of protons perunit time being extracted, which is referred to as intensity of theproton beam. The intensity of the proton beam is thus under algorithmcontrol. Further, the intensity of the proton beam is controlledseparately from the velocity of the protons in the synchrotron 130.Hence, intensity of the protons extracted and the energy of the protonsextracted are independently variable.

For example, protons initially move at an equilibrium trajectory in thesynchrotron 130. An RF field is used to excite the protons into abetatron oscillation. In one case, the frequency of the protons orbit isabout 10 MHz. In one example, in about one millisecond or after about10,000 orbits, the first protons hit an outer edge of the targetmaterial 130. The specific frequency is dependent upon the period of theorbit. Upon hitting the material 130, the protons push electrons throughthe foil to produce a current. The current is converted to voltage andamplified to yield a measured intensity signal. The measured intensitysignal is used as a feedback input to control the applied RF magnitude,RF frequency, or RF field. Preferably, the measured intensity signal iscompared to a target signal and a measure of the difference between themeasured intensity signal and target signal is used to adjust theapplied RF field in the RF cavity system 1210 in the extraction systemto control the intensity of the protons in the extraction step. Statedagain, the signal resulting from the protons striking and/or passingthrough the material 130 is used as an input in RF field modulation. Anincrease in the magnitude of the RF modulation results in protonshitting the foil or material 130 sooner. By increasing the RF, moreprotons are pushed into the foil, which results in an increasedintensity, or more protons per unit time, of protons extracted from thesynchrotron 130.

In another example, a detector external to the synchrotron 130 is usedto determine the flux of protons extracted from the synchrotron and asignal from the external detector is used to alter the RF field or RFmodulation in the RF cavity system 1210. Here the external detectorgenerates an external signal, which is used in a manner similar to themeasured intensity signal, described in the preceding paragraphs.

In yet another example, when a current from material 130 resulting fromprotons passing through or hitting material is measured beyond athreshold, the RF field modulation in the RF cavity system is terminatedor reinitiated to establish a subsequent cycle of proton beamextraction. This process is repeated to yield many cycles of proton beamextraction from the synchrotron accelerator.

In still yet another embodiment, intensity modulation of the extractedproton beam is controlled by the main controller 110. The maincontroller 110 optionally and/or additionally controls timing ofextraction of the charged particle beam and energy of the extractedproton beam.

The benefits of the system include a multi-dimensional scanning system.Particularly, the system allows independence in: (1) energy of theprotons extracted and (2) intensity of the protons extracted. That is,energy of the protons extracted is controlled by an energy controlsystem and an intensity control system controls the intensity of theextracted protons. The energy control system and intensity controlsystem are optionally independently controlled. Preferably, the maincontroller 110 controls the energy control system and the maincontroller simultaneously controls the intensity control system to yieldan extracted proton beam with controlled energy and controlled intensitywhere the controlled energy and controlled intensity are independentlyvariable. Thus the irradiation spot hitting the tumor is underindependent control of:

-   -   time;    -   energy;    -   intensity;    -   x-axis position, where the x-axis represents horizontal movement        of the proton beam relative to the patient, and    -   y-axis position, where the y-axis represents vertical movement        of the proton beam relative to the patient.

In addition, the patient is optionally independently rotated relative toa translational axis of the proton beam at the same time.

Patient Positioning

Referring now to FIG. 13, the patient is preferably positioned on orwithin a patient positioning system 1310 of the patient interface module150. The patient positioning system 1310 is used to translate thepatient and/or rotate the patient into a zone where the proton beam canscan the tumor using a proton targeting system 140, described infra.Essentially, the patient positioning system 1310 performs largemovements of the patient to place the tumor near the center of a protonbeam path 268 and the proton targeting system 140 performs finemovements of the momentary beam position 269 in targeting the tumor1520. To illustrate, FIG. 13 shows the momentary proton beam position269 and a range of scannable positions 1320 using the proton targetingsystem 140, where the scannable positions 1320 are about the tumor 1520of the patient 1530. This illustratively shows that the y-axis movementof the patient occurs on a scale of the body, such as adjustment ofabout 1, 2, 3, or 4 feet, while the scannable region of the proton beam268 covers a portion of the body, such as a region of about 1, 2, 4, 6,8, 10, or 12 inches. The patient positioning system and its rotationand/or translation of the patient combines with the proton targetingsystem to yield precise and/or accurate delivery of the protons to thetumor.

Referring still to FIG. 13, the patient positioning system 1310optionally includes a bottom unit 1312 and a top unit 1314, such asdiscs or a platform. Referring now to FIG. 13A, the patient positioningunit 1310 is preferably y-axis adjustable 1316 to allow verticalshifting of the patient relative to the proton therapy beam 268.Optionally, the distance between the bottom unit 1312 and top unit 1314is adjustable 1316 to facilitate positioning of the patient positioningconstraints 1615. Preferably, the vertical motion of the patientpositioning unit 1310 is about 10, 20, 30, or 50 centimeters per minute.Referring now to FIG. 13B, the patient positioning unit 1310 is alsopreferably rotatable 1317 about a rotation axis, such as about they-axis, to allow rotational control and positioning of the patientrelative to the proton beam path 268. Preferably the rotational motionof the patient positioning unit 1310 is about 360 degrees per minute.Optionally, the patient positioning unit rotates about 45, 90, or 180degrees. Optionally, the patient positioning unit 1310 rotates at a rateof about 45, 90, 180, 360, 720, or 1080 degrees per minute. The rotationof the positioning unit 1317 is illustrated about the rotation axis attwo distinct times, t₁ and t₂. Protons are optionally delivered to thetumor 1520 at n times where each of the n times represent differentdirections of the incident proton beam 269 hitting the patient 1530 dueto rotation of the patient 1317 about the rotation axis, such as an axisaligned with gravity.

Any of the semi-vertical, sitting, or laying patient positioningembodiments described, infra, are optionally vertically translatablealong the y-axis or rotatable about the rotation or y-axis.

Preferably, the top and bottom units 1312, 1314 move together, such thatthey rotate at the same rates and translate in position at the samerates. Optionally, the top and bottom units 1312, 1314 are independentlyadjustable along the y-axis to allow a difference in distance betweenthe top and bottom units 1312, 1314. Motors, power supplies, andmechanical assemblies for moving the top and bottom units 1312, 1314 arepreferably located out of the proton beam path 269, such as below thebottom unit 1312 and/or above the top unit 1314. This is preferable asthe patient positioning unit 1310 is preferably rotatable about 360degrees and the motors, power supplies, and mechanical assembliesinterfere with the protons if positioned in the proton beam path 269

Proton Beam Position Control

Referring now to FIG. 14, a beam delivery and tissue volume scanningsystem is illustrated. Presently, the worldwide radiotherapy communityuses a method of dose field forming using a pencil beam scanning system.In stark contrast, FIG. 14 illustrates a spot scanning system or tissuevolume scanning system. In the tissue volume scanning system, the protonbeam is controlled, in terms of transportation and distribution, usingan inexpensive and precise scanning system. The scanning system is anactive system, where the beam is focused into a spot focal point ofabout one-half, one, two, or three millimeters in diameter. The focalpoint is translated along two axes while simultaneously altering theapplied energy of the proton beam, which effectively changes the thirddimension of the focal point. The system is applicable in combinationwith the above described rotation of the body, which preferably occursin-between individual moments or cycles of proton delivery to the tumor.Optionally, the rotation of the body by the above described systemoccurs continuously and simultaneously with proton delivery to thetumor.

For example, in the illustrated system in FIG. 14A, the spot istranslated horizontally, is moved down a vertical, and is then backalong the horizontal axis. In this example, current is used to control avertical scanning system having at least one magnet. The applied currentalters the magnetic field of the vertical scanning system to control thevertical deflection of the proton beam. Similarly, a horizontal scanningmagnet system controls the horizontal deflection of the proton beam. Thedegree of transport along each axes is controlled to conform to thetumor cross-section at the given depth. The depth is controlled bychanging the energy of the proton beam. For example, the proton beamenergy is decreased, so as to define a new penetration depth, and thescanning process is repeated along the horizontal and vertical axescovering a new cross-sectional area of the tumor. Combined, the threeaxes of control allow scanning or movement of the proton beam focalpoint over the entire volume of the cancerous tumor. The time at eachspot and the direction into the body for each spot is controlled toyield the desired radiation does at each sub-volume of the cancerousvolume while distributing energy hitting outside of the tumor.

The focused beam spot volume dimension is preferably tightly controlledto a diameter of about 0.5, 1, or 2 millimeters, but is alternativelyseveral centimeters in diameter. Preferred design controls allowscanning in two directions with: (1) a vertical amplitude of about 100mm amplitude and frequency up to 200 Hz; and (2) a horizontal amplitudeof about 700 mm amplitude and frequency up to 1 Hz. More or lessamplitude in each axis is possible by altering the scanning magnetsystems.

In FIG. 14A, the proton beam is illustrated along a z-axis controlled bythe beam energy, the horizontal movement is along an x-axis, and thevertical direction is along a y-axis. The distance the protons movealong the z-axis into the tissue, in this example, is controlled by thekinetic energy of the proton. This coordinate system is arbitrary andexemplary. The actual control of the proton beam is controlled in3-dimensional space using two scanning magnet systems and by controllingthe kinetic energy of the proton beam. The use of the extraction system,described supra, allows for different scanning patterns. Particularly,the system allows simultaneous adjustment of the x-, y-, and z-axes inthe irradiation of the solid tumor. Stated again, instead of scanningalong an x,y-plane and then adjusting energy of the protons, such aswith a range modulation wheel, the system allows for moving along thez-axes while simultaneously adjusting the x- and or y-axes. Hence,rather than irradiating slices of the tumor, the tumor is optionallyirradiated in three simultaneous dimensions. For example, the tumor isirradiated around an outer edge of the tumor in three dimensions. Thenthe tumor is irradiated around an outer edge of an internal section ofthe tumor. This process is repeated until the entire tumor isirradiated. The outer edge irradiation is preferably coupled withsimultaneous rotation of the subject, such as about a vertical y-axis.This system allows for maximum efficiency of deposition of protons tothe tumor, as defined using the Bragg peak, to the tumor itself withminimal delivery of proton energy to surrounding healthy tissue.

Combined, the system allows for multi-axes control of the chargedparticle beam system in a small space with low power supply. Forexample, the system uses multiple magnets where each magnet has at leastone edge focusing effect in each turning section of the synchrotronand/or multiple magnets having concentrating magnetic field geometry, asdescribed supra. The multiple edge focusing effects in the circulatingbeam path of the synchrotron combined with the concentration geometry ofthe magnets and described extraction system yields a synchrotron having:

-   -   a small circumference system, such as less than about 50 meters;    -   a vertical proton beam size gap of about 2 cm;    -   corresponding reduced power supply requirements associated with        the reduced gap size;    -   an extraction system not requiring a newly introduced magnetic        field;    -   acceleration or deceleration of the protons during extraction;    -   simultaneous variation of x- and y-position and z-axis energy of        the charged particles; and    -   control of z-axis energy during extraction.

The result is a 3-dimensional scanning system, x-, y-, and z-axescontrol, where the z-axes control resides in the synchrotron and wherethe z-axes energy is variably controlled during the extraction processinside the synchrotron.

Referring now to FIG. 14B, an example of a proton targeting system 140used to direct the protons to the tumor with 4-dimensional scanningcontrol is provided, where the 4-dimensional scanning control is alongthe x-, y-, and z-axes along with intensity control, as described supra.A fifth axis is time. Typically, charged particles traveling along thetransport path 268 are directed through a first axis control element142, such as a vertical control, and a second axis control element 144,such as a horizontal control and into a tumor 1520. As described, supra,the extraction system also allows for simultaneous variation in thez-axis. Further, as describe, supra, the intensity or dose of theextracted beam is optionally simultaneously and independently controlledand varied. Thus instead of irradiating a slice of the tumor, as in FIG.14A, all four dimensions defining the targeting spot of the protondelivery in the tumor are simultaneously variable. The simultaneousvariation of the proton delivery spot is illustrated in FIG. 14B by thespot delivery path 269. In the illustrated case, the protons areinitially directed around an outer edge of the tumor and are thendirected around an inner radius of the tumor. Combined with rotation ofthe subject about a vertical axis, a multi-field illumination process isused where a not yet irradiated portion of the tumor is preferablyirradiated at the further distance of the tumor from the proton entrypoint into the body. This yields the greatest percentage of the protondelivery, as defined by the Bragg peak, into the tumor and minimizesdamage to peripheral healthy tissue.

Imaging System

Herein, an X-ray system is used to illustrate an imaging system.

Timing

An X-ray is preferably collected either (1) just before or (2)concurrently with treating a subject with proton therapy for a couple ofreasons.

First, movement of the body, described supra, changes the local positionof the tumor in the body relative to other body constituents. If thesubject has an X-ray taken and is then bodily moved to a protontreatment room, accurate alignment of the proton beam to the tumor isproblematic. Alignment of the proton beam to the tumor using one or moreX-rays is best performed at the time of proton delivery or in theseconds or minutes immediately prior to proton delivery and after thepatient is placed into a therapeutic body position, which is typically afixed position or partially immobilized position.

Second, the X-ray taken after positioning the patient is used forverification of proton beam alignment to a targeted position, such as atumor and/or internal organ position.

Positioning

An X-ray is preferably taken just before treating the subject to aid inpatient positioning. For positioning purposes, an X-ray of a large bodyarea is not needed. In one embodiment, an X-ray of only a local area iscollected. When collecting an X-ray, the X-ray has an X-ray path. Theproton beam has a proton beam path. Overlaying the X-ray path with theproton beam path is one method of aligning the proton beam to the tumor.However, this method involves putting the X-ray equipment into theproton beam path, taking the X-ray, and then moving the X-ray equipmentout of the beam path. This process takes time. The elapsed time whilethe X-ray equipment moves has a couple of detrimental effects. First,during the time required to move the X-ray equipment, the body moves.The resulting movement decreases precision and/or accuracy of subsequentproton beam alignment to the tumor. Second, the time require to move theX-ray equipment is time that the proton beam therapy system is not inuse, which decreases the total efficiency of the proton beam therapysystem.

Referring now to FIG. 15, in one embodiment, an X-ray is generated closeto, but not in, the proton beam path. A proton beam therapy system andan X-ray system combination 1500 is illustrated in FIG. 15. The protonbeam therapy system has a proton beam 268 in a transport system afterthe deflector 292 of the synchrotron 130. The proton beam is directed bythe targeting/delivery system 140 to a tumor 1520 of a patient 1530. TheX-ray system 1505 includes an electron beam source 1540 generating anelectron beam 1550. The electron beam is directed to an X-ray generationsource 1560, such as a piece of tungsten. Preferably, the tungsten X-raysource is located about 1, 2, 3, 5, 10, 15, or 20 millimeters from theproton beam path 268. When the electron beam 1550 hits the tungsten,X-rays are generated in all directions. X-rays are blocked with a port1562 and are selected for an X-ray beam path 1570. The X-ray beam path1570 and proton beam path 260 run substantially in parallel as theyprogress to the tumor 1520. The distance between the X-ray beam path1570 and proton beam path 269 preferably diminishes to near zero and/orthe X-ray beam path 1570 and proton beam path 269 overlap by the timethey reach the tumor 1520. Simple geometry shows this to be the casegiven the long distance, of at least a meter, between the tungsten andthe tumor 1520. The distance is illustrated as a gap 1580 in FIG. 15.The X-rays are detected at an X-ray detector 1590, which is used to forman image of the tumor 1520 and/or position of the patient 1530.

Referring again to FIG. 15, an example of an X-ray generation device1500 having an enhanced lifetime is provided. Electrons are generated ata cathode 1510, focused with a control electrode 1512, and acceleratedwith a series of accelerating electrodes 1562 and focused with focusingelectrodes 1565. The accelerated electrons 1550 impact an X-raygeneration source 1560 resulting in generated X-rays that are thendirected along an X-ray path 1570 to the subject 1530. The concentratingof the electrons from a first diameter of the cathode to a seconddiameter of the accelerated electrons 1550 allows the cathode to operateat a reduced temperature and still yield the necessary amplified levelof electrons at the X-ray generation source 1560. In one example, theX-ray generation source 1560 is the anode coupled with the cathode 1510and/or the X-ray generation source is substantially composed oftungsten.

As a whole, the system generates an X-ray beam that lies insubstantially the same path as the proton therapy beam. The X-ray beamis generated by striking a tungsten or equivalent material with anelectron beam. The X-ray generation source is located proximate to theproton beam path. Geometry of the incident electrons, geometry of theX-ray generation material, and geometry of the X-ray beam blocker 262yield an X-ray beam that runs either in substantially in parallel withthe proton beam or results in an X-ray beam path that starts proximatethe proton beam path an expands to cover and transmit through a tumorcross-sectional area to strike an X-ray detector array or film allowingimaging of the tumor from a direction and alignment of the protontherapy beam. The X-ray image is then used to control the chargedparticle beam path to accurately and precisely target the tumor, and/oris used in system verification and validation.

Patient Immobilization

Accurate and precise delivery of a proton beam to a tumor of a patientrequires: (1) positioning control of the proton beam and (2) positioningcontrol of the patient. As described, supra, the proton beam iscontrolled using algorithms and magnetic fields to a diameter of about0.5, 1, or 2 millimeters. This section addresses partial immobilization,restraint, and/or alignment of the patient to insure the tightlycontrolled proton beam efficiently hits a target tumor and notsurrounding healthy tissue as a result of patient movement.

In this section an x-, y-, and z-axes coordinate system and rotationaxis is used to describe the orientation of the patient relative to theproton beam. The z-axis represent travel of the proton beam, such as thedepth of the proton beam into the patient. When looking at the patientdown the z-axis of travel of the proton beam, the x-axis refers tomoving left or right across the patient and the y-axis refers tomovement up or down the patient. A first rotation axis is rotation ofthe patient about the y-axis and is referred to herein as a rotationaxis, bottom unit 1312 rotation axis, or y-axis of rotation. Inaddition, tilt is rotation about the x-axis, yaw is rotation about they-axis, and roll is rotation about the z-axis. In this coordinatesystem, the proton beam path 269 optionally runs in any direction. As anillustrative matter, the proton beam path running through a treatmentroom is described as running horizontally through the treatment room.

In this section, three examples of positioning are provided: (1) asemi-vertical partial immobilization system; (2) a sitting partialimmobilization system; and (3) a laying position. Elements described forone immobilization apply to other immobilization systems with smallchanges. For example, a head rest will adjust along one axis for areclined position, along a second axis for a seated position, and alonga third axis for a laying position. However, the headrest itself issimilar for each immobilization position.

Vertical Patient Positioning/Immobilization

Referring now to FIG. 16, a semi-vertical patient positioning and/orpartial immobilization system 1600 is described. The semi-verticalpatient positioning system 1600 is preferably used in conjunction withproton therapy of tumors in the torso. The patient positioning and/orimmobilization system 1600 controls and/or restricts movement of thepatient during proton beam therapy. In a first partial immobilizationembodiment, the patient is positioned in a semi-vertical position in aproton beam therapy system. As illustrated, the patient is reclining atan angle alpha, α, about 45 degrees off of the y-axis as defined by anaxis running from head to foot of the patient. More generally, thepatient is optionally completely standing in a vertical position of zerodegrees off the of y-axis or is in a semi-vertical position alpha thatis reclined about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65degrees off of the y-axis toward the z-axis.

Still referring to FIG. 16, patient positioning constraints 1615 areused to maintain the patient in a treatment position, including one ormore of: a seat support 1620, a back support 1630, a head support 1640,an arm support 1650, a knee support 1660, and a foot support 1670. Theconstraints are optionally and independently rigid or semi-rigid.Examples of a semi-rigid material include a high or low density foam ora visco-elastic foam. For example the foot support 1670 is preferablyrigid and the back support 1630 is preferably semi-rigid, such as a highdensity foam material. One or more of the positioning constraints 1615are movable and/or under computer control for rapid positioning and/orimmobilization of the patient. For example, the seat support 1620 isadjustable along a seat adjustment axis 1622, which is preferably they-axis; the back support 1630 is adjustable along a back support axis1632, which is preferably dominated by z-axis movement with a y-axiselement; the head support 1640 is adjustable along a head support axis1642, which is preferably dominated by z-axis movement with a y-axiselement; the arm support 1650 is adjustable along an arm support axis,which is preferably dominated by z-axis movement with a y-axis element;the knee support 1660 is adjustable along a knee support axis 1662,which is preferably dominated by y-axis movement with a z-axis element;and the foot support 1670 is adjustable along a foot support axis, whichis preferably dominated by y-axis movement with a z-axis element.

If the patient is not facing the incoming proton beam, then thedescription of movements of support elements along the axes change, butthe immobilization elements are the same.

Still referring to FIG. 16, an optional camera 1680 is illustrated. Thecamera views the subject 1530 creating an video image. The image isprovided to one or more operators of the charged particle beam systemand allows the operators a safety mechanism for determining if thesubject has moved or desires to terminate the proton therapy treatmentprocedure. Based on the video image, the operators may suspend orterminate the proton therapy procedure. For example, if the operatorobserves via the video image that the subject is moving, then theoperator has the option to terminate or suspend the proton therapyprocedure.

Still referring to FIG. 16, an optional video display 1690 is providedto the patient. The video display optionally presents to the patient anyof: operator instructions, system instructions, status of treatment, orentertainment.

Motors for positioning the constraints 1615, the camera 1680, and videodisplay 1690 are preferably mounted above or below the proton path 269.

Breath control is optionally performed by using the video display 1690.As the patient breathes, internal and external structures of the bodymove in both absolute terms and in relative terms. For example, theoutside of the chest cavity and internal organs both have absolute moveswith a breath. In addition, the relative position of an internal organrelative to another body component, such as an outer region of the body,a bone, support structure, or another organ, moves with each breath.Hence, for more accurate and precise tumor targeting, the proton beam ispreferably delivered at point a in time where the position of theinternal structure or tumor is well defined, such as at the bottom ofeach breath. The video display 1690 is used to help coordinate theproton beam delivery with the patient's breathing cycle. For example,the video display 1690 optionally displays to the patient a command,such as a hold breath statement, a breath statement, a countdownindicating when a breadth will next need to be held, or a countdownuntil breathing may resume.

Sitting Patient Positioning/Immobilization

In a second partial immobilization embodiment, the patient is partiallyrestrained in a seated position. The sitting restraint system hassupport structures that are similar to the support structures used inthe semi-vertical positioning system, described supra with the exceptionthat the seat support 1620 is replaced by a chair and the knee support1660 is not required. The seated restraint system generally retains theadjustable support, rotation about the y-axis, camera, video, andbreadth control parameters described in the semi-vertical embodiment,described supra.

Referring now to FIG. 17, a particular example of a sitting patientsemi-immobilization system 1700 is provided. The sitting system 1700 ispreferably used for treatment of head and neck tumors. As illustrated,the patient is positioned in a seated position on a chair 1710 forparticle therapy. The patient is further immobilized using any of the:the head support 1640, the back support 1630, a hand support 1720, theknee support 1660, and the foot support 1670. The supports 1640, 1630,1720, 1660, 1670 preferably have respective axes of adjustment 1642,1632, 1722, 1662, 1672 as illustrated. The chair 1710 is either readilyremoved to allow for use of a different patient constraint system oradapts to a new patient position, such as the semi-vertical system 1600.

Laying Patient Positioning/Immobilization

In a third partial immobilization embodiment, the patient is partiallyrestrained in a laying position. The laying restraint system has supportstructures that are similar to the support structures used in thesitting positioning system 1700 and semi-vertical positioning system1600, described supra. In the laying position, optional restraint,support, or partial immobilization elements include one or more of: thehead support 1640 and the back, hip, and shoulder support 1630. Thesupports 1640, 1630 preferably have respective axes of adjustment 1642,1632 that are rotated as appropriate for a laying position of thepatient. The laying position restraint system generally retains theadjustable supports, rotation about the y-axis, camera, video, andbreadth control parameters described in the semi-vertical embodiment,described supra.

If the patient is very sick, such as the patient has trouble standingfor a period of about one to three minutes required for treatment, thenbeing in a partially supported system can result in some movement of thepatient due to muscle strain. In this and similar situations, treatmentof a patient in a laying position on a support table is preferentiallyused. The support table has a horizontal platform to support the bulk ofthe weight of the patient. Preferably, the horizontal platform isdetachable from a treatment platform

Additionally, leg support and/or arm support elements are optionallyadded to raise, respectively, an arm or leg out of the proton beam path269 for treatment of a tumor in the torso or to move an arm or leg intothe proton beam path 269 for treatment of a tumor in the arm or leg.This increases proton delivery efficiency, as described infra.

Referring now to FIG. 18, in a laying positioning system 1800 thepatient 1530 is positioned on a platform 1610, which has a substantiallyhorizontal portion for supporting the weight of the body in a horizontalposition. For clarity of presentation, the head support 1640 and backsupport 1630 elements, though preferably present, are not illustrated.Similarly, optional hand grips 2110, 2120, though preferably used, arenot illustrated for clarity. The hand grips are described infra. One ormore leg support 1840 elements are used to position the patient's leg. Aleg support 1840 element is preferably adjustable along at least one legadjustment axis 1842 or along an arc to position the leg into the protonbeam path 269 or to remove the leg from the proton beam path 269, asdescribed infra. An arm support 1850 element is preferably adjustablealong at least one arm adjustment axis 1850 or along an arc to positionthe arm into the proton beam path 269 or to remove the arm from theproton beam path 269, as described infra. Both the leg support 1840 andarm support 1850 elements are optional.

Preferably, the patient is positioned on the platform 1610 in an area orroom outside of the proton beam path 269 and is wheeled or slid into thetreatment room or proton beam path area. For example, the patient iswheeled into the treatment room on a gurney where the top of the gurney,which is the platform 1610, detaches and is positioned onto a table1620. The platform 1610 is preferably lifted onto the table 1620 or slidonto the table 1620. In this manner, the gurney or bed need not belifted onto the table 1620.

The semi-vertical patient positioning system 1600 and sitting patientpositioning system 1700 are preferentially used to treatment of tumorsin the head or torso due to efficiency. The semi-vertical patientpositioning system 1600, sitting patient positioning system 1700, andlaying patient positioning system 1800 are all usable for treatment oftumors in the patient's limbs.

Support System Elements

Positioning constraints 1615 include all elements used to position thepatient, such as those described in the semi-vertical positioning system1600, sitting positioning system 1700, and laying positioning system1800. Preferably, positioning constraints 1615 or support systemelements are aligned in positions that do not impede or overlap theproton beam path 269. However, in some instances the positioningconstraints 1615 are in the proton beam path 269 during at least part ofthe time of treatment of the patient. For instance, a positioningconstraint 1615 element may reside in the proton beam path 269 duringpart of a time period where the patient is rotated about the y-axisduring treatment. In cases or time periods that the positioningconstraints 1615 or support system elements are in the proton beam path,then an upward adjustment of proton beam energy is preferably appliedthat increases the proton beam energy to offset the positioningconstraint 1615 element impedance of the proton beam. In one case, theproton beam energy is increased by a separate measure of the positioningconstraint 1615 element impedance determined during a reference scan ofthe positioning constraint 1615 system element or set of reference scansof the positioning constraint 1615 element as a function of rotationabout the y-axis.

For clarity, the positioning constraints 1615 or support system elementsare herein described relative to the semi-vertical positioning system1600; however, the positioning elements and descriptive x-, y-, andz-axes are adjustable to fit any coordinate system, to the sittingpositioning system 1700, or the laying positioning system 1800.

Referring now to FIG. 19 an example of a head support system 1900 isdescribed to support, align, and/or restrict movement of a human head1902. The head support system 1900 preferably has several head supportelements including any of: a back of head support 1640, a right of headalignment element 1910, and a left of head alignment element 1920. Theback of head support element is preferably curved to fit the head and isoptionally adjustable along a head support axis 1642, such as along thez-axis. Further, the head supports 1640, like the other patientpositioning constraints 1615, is preferably made of a semi-rigidmaterial, such as a low or high density foam, and has an optionalcovering, such as a plastic or leather. The right of head alignmentelement 1910 and left of head alignment elements 1920 or head alignmentelements 1910, 1920, are primarily used to semi-constrain movement ofthe head. The head alignment elements are preferably padded and flat,but optionally have a radius of curvature to fit the side of the head.The right 1910 and left 1920 head alignment elements are preferablyrespectively movable along translation axes 1912, 1922 to make contactwith the sides of the head. Restricted movement of the head duringproton therapy is important when targeting and treating tumors in thehead or neck. The head alignment elements 1910, 1920 and the back ofhead support element 1640 combine to restrict tilt, rotation or yaw,roll and/or position of the head in the x-, y-, z-axes coordinatesystem.

Referring now to FIG. 20 another example of a head support system 2000is described for positioning and/or restricting movement of a human head1902 during proton therapy of a solid tumor in the head or neck. In thissystem, the head is restrained using 1, 2, 3, 4, or more straps orbelts, which are preferably connected or replaceably connected to a backof head support element 2010. In the example illustrated, a first strap2020 pulls or positions the forehead to the support element 2010, suchas by running predominantly along the z-axis. Preferably a second strap2030 works in conjunction with the first strap 2020 to prevent the headfrom undergoing tilt, yaw, roll or moving in terms of translationalmovement on the x-, y-, and z-axes coordinate system. The second strap2030 is preferably attached or replaceable attached to the first strap2020 at or about: (1) the forehead; (2) on one or both sides of thehead; and/or (3) at or about the support element 2010. A third strap2040 preferably orientates the chin of the subject relative to thesupport element 2010 by running dominantly along the z-axis. A fourthstrap 2050 preferably runs along a predominantly y- and z-axes to holdthe chin relative to the head support element 2010 and/or proton beampath. The third 2040 strap preferably is attached to or is replaceablyattached to the fourth strap 2050 during use at or about the patient'schin. The second strap 2030 optionally connects to the fourth strap 2050at or about the support element 2010. The four straps 2020, 2030, 2040,2050 are illustrative in pathway and interconnection. Any of the strapsoptionally hold the head along different paths around the head andconnect to each other in separate fashion. Naturally, a given strappreferably runs around the head and not just on one side of the head.Any of the straps 2020, 2030, 2040, and 2050 are optionally usedindependently or in combinations or permutations with the other straps.The straps are optionally indirectly connected to each other via asupport element, such as the head support element 2010. The straps areoptionally attached to the support element 2010 using hook and looptechnology, a buckle, or fastener. Generally, the straps combine tocontrol position, front-to-back movement of the head, side-to-sidemovement of the head, tilt, yaw, roll, and/or translational position ofthe head.

The straps are preferably of known impedence to proton transmissionallowing a calculation of peak energy release along the z-axis to becalculated, such as an adjustment to the Bragg peak is made based on theslowing tendency of the straps to proton transport.

Referring now to FIG. 21, still another example of a head support 1640is described. The head support 1640 is preferably curved to fit astandard or child sized head. The head support 1640 is optionallyadjustable along a head support axis 1642. Further, the head supports1640, like the other patient positioning constraints 1615, is preferablymade of a semi-rigid material, such as a low or high density foam, andhas an optional covering, such as a plastic or leather.

Elements of the above described head support, head positioning, and headimmobilization systems are optionally used separately or in combination.

Still referring to FIG. 21, an example of the arm support 1650 isfurther described. The arm support preferably has a left hand grip 2110and a right hand grip 2120 used for aligning the upper body of thepatient 1530 through the action of the patient 1530 gripping the leftand right hand grips 2010, 2020 with the patient's hands 1534. The leftand right hand grips 2110, 2120 are preferably connected to the armsupport 1650 that supports the mass of the patient's arms. The left andright hand grips 2110, 2120 are preferably constructed using asemi-rigid material. The left and right hand grips 2110, 2120 areoptionally molded to the patient's hands to aid in alignment. The leftand right hand grips optionally have electrodes, as described supra.

Referring now to FIG. 22, an example of the back support 1630 is furtherdescribed. Referring to FIG. 22, an example of a perspective orientationof the back support 1630 is illustrated. The back support is preferablycurved to support the patient's back and to wrap onto the sides of thepatient's torso. The back support preferably has two semi-rigidportions, a left side 2210 and right side 2220. Further, the backsupport 1630 has a top end 2230 and a bottom end 2240. A first distance2250 between the top ends 2230 of the left side 2210 and right side 2220is preferably adjustable to fit the upper portion of the patient's back.A second distance 2260 between the bottom ends 2240 of the left side2210 and right side 2220 is preferably independently adjustable to fitthe lower portion of the patient's back.

Referring now to FIG. 23, an example of the knee support 1660 is furtherdescribed. The knee support preferably has a left knee support 2310 anda right knee support 2320 that are optionally connected or individuallymovable. Both the left and right knee supports 2310, 2320 are preferablycurved to fit standard sized knees 1532. The left knee support 2310 isoptionally adjustable along a left knee support axis 2312 and the rightknee support 2320 is optionally adjustable along a right knee supportaxis 2322. Alternatively, the left and right knee supports 2310, 2320are connected and movable along the knee support axis 1662. Both theleft and right knee supports 2310, 2320, like the other patientpositioning constraints 1615, are preferably made of a semi-rigidmaterial, such as a low or high density foam, having an optionalcovering, such as a plastic or leather.

Positioning System Computer Control

One or more of the patient positioning unit 1610 components and/or oneof more of the patient positioning constraints 1615 are preferably undercomputer control, where the computer control positioning devices, suchas via a series of motors and drives, to reproducibly position thepatient. For example, the patient is initially positioned andconstrained by the patient positioning constraints 1615. The position ofeach of the patient positioning constraints 1615 is recorded and savedby the main controller 110, by a sub-controller or the main controller110, or by a separate computer controller. Then, medical devices areused to locate the tumor 1520 in the patient 1530 while the patient isin the orientation of final treatment. The imaging system 170 includesone or more of: MRI's, X-rays, CT's, proton beam tomography, and thelike. Time optionally passes at this point where images from the imagingsystem 170 are analyzed and a proton therapy treatment plan is devised.The patient may exit the constraint system during this time period,which may be minutes, hours, or days. Upon return of the patient to thepatient positioning unit 1610, the computer can return the patientpositioning constraints 1615 to the recorded positions. This systemallows for rapid repositioning of the patient to the position usedduring imaging and development of the treatment plan, which minimizessetup time of patient positioning and maximizes time that the chargedparticle beam system 100 is used for cancer treatment.

Proton Delivery Efficiency

A Bragg peak energy profile shows that protons deliver their energyacross the entire length of the body penetrated by the proton up to amaximum penetration depth. As a result, energy is being delivered tohealthy tissue, bone, and other body constituents before the proton beamhits the tumor. It follows that the shorter the pathlength in the bodyprior to the tumor, the higher the efficiency of proton deliveryefficiency, where proton delivery efficiency is a measure of how muchenergy is delivered to the tumor relative to healthy portions of thepatient. Examples of proton delivery efficiency include: (1) a ratioproton energy delivered the tumor and proton energy delivered tonon-tumor tissue; (2) pathlength of protons in the tumor versuspathlength in the non-tumor tissue; and (3) damage to a tumor comparedto damage to healthy body parts. Any of these measures are optionallyweighted by damage to sensitive tissue, such as a nervous systemelement, heart, brain, or other organ. To illustrate, for a patient in alaying position where the patient is rotated about the y-axis duringtreatment, a tumor near the hear would at times be treated with protonsrunning through the head-to-heart path, leg-to-heart path, orhip-to-heart path, which are all inefficient compared to a patient in asitting or semi-vertical position where the protons are all deliveredthrough a shorter chest-to-heart; side-of-body-to-heart, orback-to-heart path. Particularly, compared to a laying position, using asitting or semi-vertical position of the patient, a shorter pathlengththrough the body to a tumor is provided to a tumor located in the torsoor head, which is a higher or better proton delivery efficiency.

Herein proton delivery efficiency is separately described from the timeefficiency or synchrotron use efficiency, which is a fraction of timethat the charged particle beam apparatus is in operation.

Patient Placement

Preferably, the patient 1530 is aligned in the proton beam path 269 in aprecise and accurate manner. Several placement systems are described.The patient placement systems are described using the laying positioningsystem 1800, but are equally applicable to the semi-vertical 1600 andsitting 1700 positioning systems.

In a first placement system, the patient 1530 is positioned in a knownlocation relative to the platform 1810. For example, one or more of thepositioning constraints 1615 position the patient 1530 in a preciseand/or accurate location on the platform 1810. Optionally, a placementconstraint element 1535 connected or replaceably connected to theplatform 1810 is used to position the patient on the platform. Theplacement constraint element(s) is used to position any position of thepatient, such as a hand, limb, head, or torso element.

In a second placement system, one or more positioning constraints 1615or support element, such as the platform 1810, is aligned versus anelement in the patient treatment room. Essentially a lock and key systemis optionally used, where a lock 1830 fits a key 1835. The lock and keyelements combine to locate the patient relative to the proton beam path269 in terms of any of the x-, y-, and z-position, tilt, yaw, and roll.Essentially the lock is a first registration element and the key is asecond registration element fitting into, adjacent to, or with the firstregistration element to fix the patient location and/or a supportelement location relative to the proton beam path 269. Examples of aregistration element include any of a mechanical element, such as amechanical stop, and an electrical connection indicating relativeposition or contact.

In a third placement system, the imaging system, described supra, isused to determine where the patient is relative to the proton beam path269 or relative to an imaging marker 1860 placed in an support elementor structure holding the patient, such as in the platform 1810. Whenusing the imaging system, such as an X-ray imaging system, then thefirst placement system or positioning constraints 1615 minimize patientmovement once the imaging system determines location of the subject.Similarly, when using the imaging system, such as an X-ray imagingsystem, then the first placement system and/or second positioning systemprovide a crude position of the patient relative to the proton beam path269 and the imaging system subsequently determines a fine position ofthe patient relative to the proton beam path 269.

Monitoring Breathing

Preferably, the patient's breathing pattern is monitored. When asubject, also referred to herein as a patient, is breathing manyportions of the body move with each breath. For example, when a subjectbreathes the lungs move as do relative positions of organs within thebody, such as the stomach, kidneys, liver, chest muscles, skin, heart,and lungs. Generally, most or all parts of the torso move with eachbreath. Indeed, the inventors have recognized that in addition to motionof the torso with each breath, various motion also exists in the headand limbs with each breath. Motion is to be considered in delivery of aproton dose to the body as the protons are preferentially delivered tothe tumor and not to surrounding tissue. Motion thus results in anambiguity in where the tumor resides relative to the beam path. Topartially overcome this concern, protons are preferentially delivered atthe same point in each of a series of breathing cycles.

Initially a rhythmic pattern of breathing of a subject is determined.The cycle is observed or measured. For example, a proton beam operatorcan observe when a subject is breathing or is between breaths and cantime the delivery of the protons to a given period of each breath.Alternatively, the subject is told to inhale, exhale, and/or hold theirbreath and the protons are delivered during the commanded time period.

Preferably, one or more sensors are used to determine the breathingcycle of the individual. Two examples of a breath monitoring system areprovided: (1) a thermal monitoring system and (2) a force monitoringsystem.

Referring again to FIG. 20, an example of the thermal breath monitoringsystem is provided. In the thermal breath monitoring system, a sensor isplaced by the nose and/or mouth of the patient. As the jaw of thepatient is optionally constrained, as described supra, the thermalbreath monitoring system is preferably placed by the patient's noseexhalation path. To avoid steric interference of the thermal sensorsystem components with proton therapy, the thermal breath monitoringsystem is preferably used when treating a tumor not located in the heador neck, such as a when treating a tumor in the torso or limbs. In thethermal monitoring system, a first thermal resistor 2065 is used tomonitor the patient's breathing cycle and/or location in the patient'sbreathing cycle. Preferably, the first thermal resistor 2065 is placedby the patient's nose, such that the patient exhaling through their noseonto the first thermal resistor 2050 warms the first thermal resistor2065 indicating an exhale. Preferably, a second thermal resistor 2060operates as an environmental temperature sensor. The second thermalresistor 2060 is preferably placed out of the exhalation path of thepatient but in the same local room environment as the first thermalresistor 2065. Generated signal, such as current from the thermalresistors 2065, 2060, is preferably converted to voltage andcommunicated with the main controller 110 or a sub-controller of themain controller. Preferably, the second thermal resistor 2060 is used toadjust for the environmental temperature fluctuation that is part of asignal of the first thermal resistor 2065, such as by calculating adifference between the values of the thermal resistors 2065, 2060 toyield a more accurate reading of the patient's breathing cycle.

Referring again to FIG. 17, an example of the force/pressure breathmonitoring system is provided. In the force breath monitoring system, asensor is placed by the torso. To avoid steric interference of the forcesensor system components with proton therapy, the force breathmonitoring system is preferably used when treating a tumor located inthe head, neck or limbs. In the force monitoring system, a belt or strap1730 is placed around an area of the patient's torso that expands andcontracts with each breath cycle of the patient. The belt 1730 ispreferably tight about the patient's chest and is flexible. A forcemeter 1732 is attached to the belt and senses the patients breathingpattern. The forces applied to the force meter 1732 correlate withperiods of the breathing cycle. The signals from the force meter 1732are preferably communicated with the main controller 110 or asub-controller of the main controller.

Breath Control

Once the rhythmic pattern of the subject's breathing is determined, asignal is optionally delivered to the subject to more precisely controlthe breathing frequency. For example, a display screen is placed infront of the subject directing the subject when to hold their breath andwhen to breath. Typically, a breathing control module uses input fromone or more of the breathing sensors. For example, the input is used todetermine when the next breath exhale is to complete. At the bottom ofthe breath, the control module displays a hold breath signal to thesubject, such as on a monitor, via an oral signal, digitized andautomatically generated voice command, or via a visual control signal.Preferably, a display monitor is positioned in front of the subject andthe display monitor displays at least breathing commands to the subject.Typically, the subject is directed to hold their breath for a shortperiod of time, such as about one-half, one, two, or three seconds. Theperiod of time the subject is asked to hold their breath is less thanabout ten seconds. The period of time the breath is held is preferablysynchronized to the delivery time of the proton beam to the tumor, whichis about one-half, one, two, or three seconds. While delivery of theprotons at the bottom of the breath is preferred, protons are optionallydelivered at any point in the breathing cycle, such as upon fullinhalation. Delivery at the top of the breath or when the patient isdirected to inhale deeply and hold their breath by the breathing controlmodule is optionally performed as at the top of the breath the chestcavity is largest and for some tumors the distance between the tumor andsurrounding tissue is maximized or the surrounding tissue is rarefied asa result of the increased volume. Hence, protons hitting surroundingtissue is minimized. Optionally, the display screen tells the subjectwhen they are about to be asked to hold their breath, such as with a 3,2, 1, second countdown so that the subject is aware of the task they areabout to be asked to perform.

Proton Beam Therapy Synchronization with Breathing

A proton delivery control algorithm is used to synchronize delivery ofthe protons to the tumor within a given period of each breath, such asat the top or bottom of a breath when the subject is holding theirbreath. The proton delivery control algorithm is preferably integratedwith the breathing control module. Thus, the proton delivery controlalgorithm knows when the subject is breathing, where in the breath cyclethe subject is, and/or when the subject is holding their breath. Theproton delivery control algorithm controls when protons are injectedand/or inflected into the synchrotron, when an RF signal is applied toinduce an oscillation, as described supra, and when a DC voltage isapplied to extract protons from the synchrotron, as described supra.Typically, the proton delivery control algorithm initiates protoninflection and subsequent RF induced oscillation before the subject isdirected to hold their breath or before the identified period of thebreathing cycle selected for a proton delivery time. In this manner, theproton delivery control algorithm can deliver protons at a selectedperiod of the breathing cycle by simultaneously or nearly simultaneouslydelivering the high DC voltage to the second pair of plates, describedsupra, which results in extraction of the protons from the synchrotronand subsequent delivery to the subject at the selected time point. Sincethe period of acceleration of protons in the synchrotron is constant orknown for a desired energy level of the proton beam, the proton deliverycontrol algorithm is used to set an AC RF signal that matches thebreathing cycle or directed breathing cycle of the subject.

Multi-Field Illumination

The 3-dimensional scanning system of the proton spot focal point,described supra, is preferably combined with a rotation/raster method.The method includes layer wise tumor irradiation from many directions.During a given irradiation slice, the proton beam energy is continuouslychanged according to the tissue's density in front of the tumor toresult in the beam stopping point, defined by the Bragg peak, to alwaysbe inside the tumor and inside the irradiated slice. The novel methodallows for irradiation from many directions, referred to herein asmulti-field irradiation, to achieve the maximal effective dose at thetumor level while simultaneously significantly reducing possibleside-effects on the surrounding healthy tissues in comparison withexisting methods. Essentially, the multi-field irradiation systemdistributes dose-distribution at tissue depths not yet reaching thetumor.

An example further illustrates a method and apparatus using the abovedescribed elements and techniques. An apparatus for positioning apatient relative to charged particles extracted from a synchrotron forirradiation therapy of a tumor of a patient, optionally includes aplatform configured to support the patient, where the platform includesmulti-axis computer control of a rotation and/or vertical position ofthe platform. Preferably, at least a portion of the platform is locatedunder an about horizontal beam path of the charged particles extractedfrom said synchrotron. Preferably, the platform rotates to at least tenrotation positions over at least about one hundred eighty degrees ofrotation during a tumor treatment period. Optionally, the rotationposition and/or the vertical position of the platform is variedsimultaneous with delivery of the charged particles from thesynchrotron. Optionally, a rotational reamer adjust rotation position ofthe platform at a rate in excess of ninety degrees per minute, such asabout 360 degrees per minute. A vertical reamer is optionally used toadjust vertical position of the platform at a rate in excess of onecentimeter per second and preferably about 5, 10, or 20 centimeters persecond. Optionally, the synchrotron is configures with any of the abovedescribed elements. Optionally, energy and/or intensity of the extractedcharged particle beam is varies simultaneously with any of rotation ofthe patient, X-ray scanning of the patients, charged particle delivery,axial to the path of the particle beam horizontal scanning of thecharged particle beam, and vertical scanning of the charged particlebeam.

Although the invention has been described herein with reference tocertain preferred embodiments, one skilled in the art will readilyappreciate that other applications may be substituted for those setforth herein without departing from the spirit and scope of the presentinvention. Accordingly, the invention should only be limited by theClaims included below.

1. An apparatus for positioning a patient relative to charged particlesextracted from a synchrotron for irradiation therapy of a tumor of apatient, comprising: a platform configured to support the patient, saidplatform comprising multi-axis computer control of: a vertical positionof said platform; and a rotation position of said platform, wherein atleast a portion of said platform comprises a position under an abouthorizontal beam path of the charged particles extracted from saidsynchrotron, said platform configured to rotate, under computer control,to at least ten rotation positions over at least about one hundredeighty degrees of rotation during a tumor treatment period, and whereinsaid control of position positions the tumor in the about horizontalbeam path during use.
 2. The apparatus of claim 1, said platformconfigured to adjust at least one of said rotation position and saidvertical position simultaneous with delivery of the charged particlesfrom said synchrotron.
 3. The apparatus of claim 1, further comprising arotational reamer configured to adjust said rotation position of saidplatform at a rate in excess of ninety degrees per minute simultaneouswith a period of delivery of the charged particles to the tumor.
 4. Theapparatus of claim 3, further comprising a vertical reamer configured toadjust said vertical position of said platform at a rate in excess ofone centimeter per second.
 5. The apparatus of claim 1, wherein deliveryof the charged particles in said at least ten rotation positionscircumferentially distributes ingress energy of the charged particles toa corresponding at least ten areas circumferentially distributed aboutthe tumor.
 6. The apparatus of claim 1, said synchrotron configured tosimultaneously vary energy and intensity of the charged particles
 7. Theapparatus of claim 1, further comprising: an X-ray source configuredwithin about twenty millimeters of the about horizontal beam path of thecharged particles extracted from said synchrotron, said X-ray sourcegenerating a tumor location signal, said tumor location signal used insetting said rotation position and said vertical position of saidplatform.
 8. An apparatus for positioning a patient for irradiation of atumor with charged particles extracted from a synchrotron, comprising: alower support unit; at least one patient positioning device, said lowersupport unit supporting said patient positioning device; and means forrotating said lower support unit about an about vertical axis to aplurality of rotation positions, wherein said plurality of rotationpositions comprises at least five computer controlled rotation positionsin a period of less than two minutes during irradiation of the tumor bythe charged particles, said synchrotron configured to deliver thecharged particles along an about horizontal axis over a portion of saidlower support unit.
 9. The apparatus of claim 8, further comprisingmotors configured to adjust rotation position of both said lower supportunit and vertical position of said lower support unit during delivery ofthe charged particles from said synchrotron.
 10. The apparatus of claim8, further comprising: an upper support unit mechanically connected tosaid lower support unit, said means for rotating said lower support unitin synchronization with said upper support unit.
 11. The apparatus ofclaim 10, further comprising: a first thermal resistor held by saidupper support unit, said first thermal resistor configured in anexhalation path of the patient; a second thermal resistor configured tosense environmental temperature out of the exhalation path; and acontroller using at least one reading from said first thermal resistorand said second thermal resistor to determine a respiration cycle of thepatient, wherein said controller controls delivery of the chargedparticles from said synchrotron in phase with said respiration cycle.12. The apparatus of claim 8, further comprising: a motor for adjustingdistance between said lower support unit and said upper support unit.13. The apparatus of claim 8, further comprising: means for verticallyadjusting said lower support unit, wherein said means for verticallyadjusting adjusts the tumor of the patient to overlap the chargedparticles extracted from said synchrotron.
 14. The apparatus of claim 8,said patient positioning device further comprising: a semi-uprightpatient support surface, said semi-upright patient support surfacereclined from said about vertical axis by less than about sixty-fivedegrees, said semi-upright support surface configured to constrainmovement of the patient during delivery of the charged particles. 15.The apparatus of claim 8, further comprising independent control of allof: a vertical position of said rotatable platform; a rotation positionof said rotatable platform; energy of the charged particles; andintensity of the charged particles, wherein delivery of the chargedparticles comprises delivery at a repeating period, said periodconfigured at a periodic time period of the patient's respiration cycleand in coordination with rotation of the patient on said rotatableplatform during said plurality of rotation positions.
 16. The apparatusof claim 8, said apparatus further comprising control of all of: anx-axis position of the charged particles; a y-axis position of thecharged particles; energy of the charged particles; and intensity of thecharged particles, wherein said intensity comprises control through useof a feedback control using a current generated by the charged particlestransmitting through a foil in an extraction process of the chargedparticles at said energy.
 17. A method for positioning a patientrelative to charged particles extracted from a synchrotron forirradiation therapy of a tumor of a patient, comprising the steps of:supporting the patient on a platform; computer controlling a verticalposition of said platform; computer controlling a rotation position ofsaid platform, wherein at least a portion of said platform comprises aposition under an about horizontal beam path of the charged particlesextracted from said synchrotron; rotating said platform, under computercontrol, to at least ten rotation positions over at least about onehundred eighty degrees of rotation during a tumor treatment period; andpositioning the tumor of the patient with said platform in the abouthorizontal beam path during use.
 18. The method of claim 17, furthercomprising the step of: adjusting at least one of said rotation positionand said vertical position simultaneous with delivery of the chargedparticles from said synchrotron.
 19. The method of claim 17, furthercomprising the step of: circumferentially distributing ingress energy ofthe charged particles to at least ten areas circumferentiallydistributed about the tumor corresponding to said at least ten rotationpositions.
 20. The method of claim 17, further comprising the step of:simultaneously varying at least one of energy and intensity of thecharged particles during said step of rotating.
 21. The method of claim20, further comprising the steps of: generating a tumor location signalusing an X-ray source configured within about twenty millimeters of theabout horizontal beam path of the charged particles extracted from saidsynchrotron; and setting said rotation position of said platform usingsaid tumor location signal.
 22. The method of claim 17, furthercomprising the steps of: using a thermal resistor configured in anexhalation path of the patient to establish a respiration pattern of thepatient; and delivering the charged particles from said synchrotron inphase with said respiration pattern.
 23. The method of claim 17, furthercomprising the step of: supporting the patient on a semi-upright patientsupport surface held by said lower support unit, said semi-uprightpatient support surface reclined from said about vertical axis by lessthan about sixty-five degrees, said semi-upright support surfaceconfigured to constrain movement of the patient during delivery of thecharged particles.
 24. The method of claim 17, further comprising thesteps of: controlling energy of the charged particles; controllingintensity of the charged particles; and delivering the charged particlesat a repeating period, said period correlated to a rhythmic pattern ofthe patient's respiration cycle.
 25. The method of claim 17, furthercomprising the steps of: after said step of positioning, collectingmulti-field images of the tumor in the patient; developing a tumorirradiation plan; repositioning the tumor using said platform; andirradiating the tumor with the charged particles in each of said atleast ten rotation positions.
 26. The method of claim 17, furthercomprising the steps of: controlling energy of the charged particlesusing a magnetic field in a bending magnet of said synchrotron, saidbending magnet comprising: a tapered iron based core adjacent a gap,said core comprising a surface polish of less than about ten micronsroughness; and a focusing geometry comprising: a first cross-sectionaldistance of said iron based core forming an edge of said gap, and asecond cross-sectional distance of said iron based core not in contactwith said gap, wherein said second cross-sectional distance comprises alength at least fifty percent larger than said first cross-sectionaldistance, said first cross-sectional distance running parallel with saidsecond cross-sectional distance.
 27. The method of claim 17, furthercomprising the step of: varying intensity of the charged particlesdependent upon efficiency of delivery of energy of the charged particleswithin the tumor versus delivery of energy of the charged particles tohealthy tissue of the patient.
 28. The method of claim 17, furthercomprising the step of: accelerating the charged particles in a chargedparticle circulation beam path running about a center of saidsynchrotron, said charged particle circulation beam path comprising:straight sections; and turning sections, wherein each of said turningsections comprises a plurality of bending magnets, wherein saidcirculation beam path comprises a length of less than sixty meters, andwherein a number of said straight sections equals a number of saidturning sections.